ProDave

You will be treating the wood with something won't you? If it were me, I would paint both sides of the mating t&g profiles before slotting them together to protect from water that WILL get in the gap

It's one sentence and a rectangle box drawn on the plans to get official permission for the static caravan. But plenty just do it without explicitly getting permission. You will need some drainage system to connect it to, so it may mean your first job is to get services installed and a treatment plant for example if you need one so the 'van is habitable.

We had a variation of this in the old 1930's semi I used to own. That was 9" solid brick walls no cavity. The stuff used there was very thin polystyrene on a roll, fitted with wallpaper paste and then papered over. It did make the wall feel warmer to the touch than other bare bits of wall and it seemed to stop condensation. I doubt it made much of a difference to the heating bills.

It should pump up to and hold at the level of "seal" in the smallest trap. Any attempt to go above that just blows bubbles through the trap. I think 80mm was my smallest trap. If you can get to 20 and it holds where previously you got higher, go and check ALL the traps in the house are full, by pouring some water down them. If one has not been used for a while some of the water in it may have evaporated.

What covenant do you think you might be breaching? We extended a previous house in breach of a covenant "No building without the permission of xxxx Council" I mistook getting planning and building regs from that council as having their permission under that covenant. It was not until we sold the property that the buyers solicitor said we were in breach of that covenant and that is when we bought the indemnity policy to allow the sale to proceed.

This of course show the "replace gas boilers with a heat pump" is NOT a simple swap in the majority of cases. I think most of us new that, but it is not the impression being given to the general public.

It really did do a good job of showing just how hopeless the present plan is. No hope of getting enough heat pumps installed and houses insulation upgraded. No hope of getting enough green energy built in time and the electricity grid upgraded to cope. No hope of getting enough new nuclear built on time. No hope of Hydrogen ever being a viable green energy source. The spokesperson they kept putting these points to had no answer other than waffle and pretend all was okay.

They are featuring an £18,000 heat pump install. They say the heat pump costs about £4000 and "takes a team of 6 over a week to install" So lets say 18 man days? and lets say £400 per day each, that's £7200 labour. Lets say £1500 for new hot water tank and controls, and £2000 for new radiators (that one is a pure guess) I still only get to £14700

It will be interesting if they analyse the present costs of a heat pump install to see if they are reasonable. Somehow I doubt they will.

Have you chosen your stove yet? some like the one we bought can be fitted just 100mm from combustible materials and ours is just over 1oomm from plasterboard.

Unlikely to be successful. If the builder supplies stuff "supply and fit" on a new build it must be zero rated for VAT. If he supplies stuff but does not fit it, he is right to charge VAT but you will be unlikely to be able to re claim that. If buying stuff for self install, buy it in your own name so your name is on the VAT receipt so you are guaranteed to be able to claim it.

Well as @joe90 said, Just stop Oil want us to stop using oil right now. Totally unrealistic. We are transitioning to more renewable generation, just as fast as wind farms and the electricity distribution network can be built. Banging on to "the public" about the need for change is not going to speed that up. We have already discussed how there are artificial hurdles put in the way of installing heat pumps. Buying an electric car now is just likely to result in more fossil fuelled electricity to charge them. Constantly being told "we" are not doing enough just makes me feel like "well I bloody well will buy a historic V8 petrol Range Rover and drive it all around the London LEZ then"

Sounds to me like a realisation of reality, that it is simply not possible to power everything from renewables and a realisation that electricity demand will double. I think it is the first time i have seen such an admission. What strikes me given the growth in electricity demand and the growth in renewable generation, which we know to be rather dependant on the weather hence unreliable, is just how little energy storage there is in that mixture. I have said for a while people are more likely to get on board and support the changes if the targets are realistic and achievable, and some praise is given for the progress we have already made. Set an unachievable target, and treat everyone as though nobody has done a thing yet to reduce emissions and you get a disinterested public.

The first thing I say is do you really really want the HW cylinder in the plant room? Only put it there is the plant room is central to all points of hot water use to minimise HW delivery time. If not, the HW cylinder is often better placed in an airing cupboard elsewhere in the house that is central to all points of HW use.

The main feed will be to the wiring centre. so FCU there. From there you will need a minimum of permanent L and N and switched L (call for heat) to the boiler. So use a 3 core and earth for that, and locally a 3 pole fan isolator switch would do the job of local boiler isolation.

A stone mason would make and install such an arch. It is not an off the shelf product, and it is not a trivial amount of work to fit it either.

Ah this is a "clever" pump, controlled by an APP. Sorry I will bow out here, it is far too complicated and wants to make up it's own mind when and how to run. Not what I would want in my system.

Are you employing an architect or other designer to specify the details of the building and get the building regs approval or are you doing it all yourself? By far the best approach is insulate the hell out of the building and make it air tight. If you are needing to add things like solar PV just to get a SAP pass, then the building itself is not really good enough.

Can you post a picture and more details of this "wiring centre" Without knowing what is controlling the pump, nobody can say id it operating how the system was designed or not. If designed properly, of course the pump will not run when there is no demand.

Do you mean the tank is making a noise when heating DHW, perhaps a rattling sort of sound coming from inside the tank? I had this with my Telford tank. By trial and error I cured it by opening up the bypass valve so it was bypassing water all the time. I think the issue was the heat pump demands such a high water flow rate, that flow rate was more than the tank input coil was happy with. I couldn't just turn down the pump or the HP would trip on low water flow rate, so allowing some water to bypass the tank seemed to "fix" it.

Is the underside of the B&B structure higher than outside ground level?

Then you end up with stud spacing that does not match plasterboard sheet sizes, setting yourself an other problem to solve.

Any competent electrician can fit a diverter so just get that done when the tank is installed.

https://www.screwfix.com/p/crabtree-capital-50a-1-way-pull-cord-switch-white-with-neon/90597

What is needed, is someone who has had a BUS / MCS heat pump install to come and tell us exactly what it cost, exactly how many man hours of workman time took place at their house, and exactly what heat pump and other equipment was installed. Then we could pick it apart into a material cost, and a reasonable labour cost, and see what the "MCS premium" really was. Without that all I can say is "me and my plumber mate could fit it a lot cheaper"