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Just saying that the detail around a zinc standing seam is likely to be somewhat different to the version you posted about before. Zinc can be soldered/custom formed in a way that steel can't. Seems to me that you might be underestimating how much time you need to get this (plus everything else done). That is a good idea if it can be done without too much extra effort (or if it saves a lot of effort that would otherwise be spent dealing with the MHVR). If you aren't really targetting a specific size for the roof space - just enough for MHVR and maybe some other plant then there maybe options that avoid the tricky bits. Simplist that comes to mind is insulate under rather than between the rafters (losing space but its easier). Need to think about airtightness carefully though.

Show us a photo of what you have? If I were doing it I would look to space each additional cable quite a way away from the the previous join. Bundling them all together will make for an inflexible section. Are you using stranded or solid core cable?

You had another thread recently about trusses vs hand cut roof. If you aren't trying to vault the ceiling or preserve the option to build additional rooms in the roof then going for bog standard trusses is more attractive than otherwise. If planning a future expansion into the loft then I understand the placement of the insulation. If not, is it possible that the architect is working of old or incorrect assumptions? If so could be building in extra cost/complexity in other areas too. Edit: Also note your plans say zinc roof whereas another thread suggested youd choosen something else.

Given you want roof integrated solar. Make sure your roof make up is compatible. Specifically about fire resistance. I'm pretty sure I've seen that requirements have got tougher recently. Sorry can't remember more or point you to anything specific.

I'm definitely in the camp of wanting as many panels as possible (even on the north side of a roof if the roof pitch is relatively shallow). Maximizing winter production using large numbers of panels seemed more cost effective than pretty much any other energy efficiency measure (when I last sat down and did some costing on this which is a while ago). The Viridian system looks good, whether it's worth the premium though idk. Proprietary panels always a concern but if doing roof trays then you are locked into a fixed size panel whatever you do (make sure you get spares/have a guaranteed ability to replace them in case you get unlucky with a hail storm or similar). The latest Viridian panel seems pretty up to date, glass-on-glass which is good to see (as last time I looked the more proprietary systems seemed to be a few steps behind the latest panels.

What is included? Panels themselves should be closer to £30/m^2, double that once you include the trays. Am I missing something? https://www.bimblesolar.com/solar/solar-pallets/PALLET-C455

Again, not got knowledge of the specifc hinge. But just because a normal spanner doesn't fit doesn't mean its not there for adjustment. Slim tools exist and wouldn't be a surprising requirement: https://www.amazon.co.uk/sourcing-map-Galvanizing-Automotive-Furniture/dp/B0DRP7YZF9?sr=8-8 The above are cheapo ones as I know you are on a budget. Its possible they are too weak for your needs (but amazon has easy returns).

Don't cap it. Leave the other side open while you fit the stop cock then turn the stop cock off. Can be done without too much mess (outside).

It's about the third significant tangent so far on this thread. In the running for most diverted topic of the year!

In a world where funds are limited and we have to make choices about how to spend them it just makes far more sense to spend 20k upgrading 10 houses to support heatpumps vs gas (or oil) vs upgrading one hobbyist who needs a large amount of power occasionally. The carbon emissions from your diesel compressor will be relatively tiny compared to those saved from 10 houses given you only use it occasionally. I'd hazard a guess that if you used your compressor a lot the fuel bills would be large enough to make the 20k fee look like a good deal.

Though forklift batteries are a long way away from being ideal for this sort of system. You'll get much less out of them than an equivalent modern LFP pack per charge and they will degrade more quickly. So if used very occasionally and free thats fine but don't plan on using them for grid arbitrage or daily cycling.

You would, but the question is do you need that extra cooling? If you don't actually need it to achieve the temperatures you want then it's an over complication to install it.

25mm likely buys you enough room for the clamp. If you have a row or a grid of lights and have one out of place its going to look awful but if you haven't done any of them yet can't you adjust the overall spacing a touch to create room?

The assesor is probably a contractor working for a private company that charges a nice big administration fee on top of the raw costs.

I think this country would likely have far fewer claimants long term if we actually treated people with respect and helped them back into work. Would cost a lot more at first though and there would always be a small percentage taking advantage so can't see it happening.

Sorry I slightly misspoke. I meant earth. If you are in a vehicle your electrical system will not be connected to earth. You will ground your system to the negative battery terminal (and likely chassis of vehicle) but the tires will isolate your system from earth. There are some different rules for systems like this to normal domestic systems. I'm not an electrician and thats about as far as my memory goes (from looking at this out of curiosity a while ago). My comment was made more from the perspective as I saw what the others had said in this thread seemed to be coming from the perspective of a domestic system and wanted to cover the possibility that you read them as such and thought you could ignore them because your situation is different. Having read your reply it seems like you have all the bits you need for protection so my point is somewhat moot.

Has been discussed previously.

I tend to agree but at this point I'm out of knowledge/experience to help. I'm sure others will step in if further help is needed. Seems like the natural state of things. Humans tend to underestimate the complexity of things they don't understand/lack experience in and while we learn the specific case we don't necessarily adjust our handling of future unknowns. Good luck!

I apologise I just re-read your original post. A victron charge controller for 15A 100V (so 2 strings of two panels) is about £70 so not much difference than the cost of a panel and does buy you some redunancy (which is useful if you go on trips to the middle of nowhere). At 70V on a system isolated from ground safety concerns are less than a traditional system but you do stlil need to pay close attention to them.

I assume you have a battery to run off during the night. Disconnecting the solar panels from the charge controller shouldnt interfere with your consumers. I know you said you didn't want to think about a second charge controller but I wonder why? It seems like an easy option and not expensive. Are you using an ecoflex or similar?

IIRC Roger has an offer to go to 80A for free but no more and no three phase which Roger wants for other reasons (workshop). Even for a house with relatively poor insulation I would have thought a heat pump could be made to work within the supply constraints. Skill Builder had a series of videos on Youtube where they looked at a property that had a badly installed heatpump that didn't do the job and heatgeek came in and fixed up the system and ended up with a happy customer. They installed some cheap loft insulation but otherwise the property was old solid walls, etc, at least for a large part of it.

I can't see how an annual property tax replaces stamp duty easily (from a government perspective). The talk I've read is about an annual property tax replacing council tax with CGT replacing stamp duty. I can see how that would make sense and likely be a relatively positive thing if done purely on a cost neutral basis (not that any government would do it on that basis). Also not sure how exempting people who had paid stamp duty on their purchase would allow any change to work. If the governments reason for making the change is to raise money but do it as part of a reform that raises the money in a 'fairer'* way than just raising existing taxes, then giving every current property owner an exemption would mean the policy will raise less money than the current policy for potentially decades as the housing market turns over. * whether whatever policy they come up with is actually seen as fairer overall I reserve judgement. Seems likely to be quite unfair to people who happen to live in London and surrounds.

Yeh if a loxone bulb cost £20 rather than £80 they might have something but the prices compared to standard off the shelf are crazy. I'm guessing the price on the website can be got down a fair bit through a bulk order but still. Having looked again at their website thanks to their thread at least they now seem to have fittings with decent lenses, etc. I doubt we will get there as standard in domestic properties in any time scale relevant to this forum.

That sounds like the best approach to keep things standard and understandable. GU10 seems to have won the war for replaceable bulb fittings even though its the worst format for dimmable LEDs.

I checked, my old MR16 drivers are AC. First hit for MR16 driver now came up with a DC driver.