ProDave

Isolation is a good point. The problem is having a live source from 2 houses at one of the wiring centres. Make sure each house has it's own wiring centre to take care of the thermostats, time clocks and actuating the motorised valves. Use a (probably modified) wireless thermostat system to send the "call for heat" from each houses motorised valves to the boiler from the 2 properties.

You discharge to a watercourse when the ground conditions won't work for a soakaway. They work on the principle of dilution. If there is no flow there is no dilution.

Re the pantry. Plan right at the start where that is going, and DO NOT put the under floor heating pipes under that space. Definitely worth having a pair of LPG cylinders just for a gas hob. I say a pair, on an automatic changeover valve, because they last so long (>1 year) you will forget about them so you need the spare full one sitting there ready. Everything else you mention you will get from a Howdens kitchen.

It is all down to "what" soil goes down to 1000mm at the "deep end" It someone in the past has piled it up with extra top soil to level the ground then that means more digging and deeper foundations at that end. What do you hit at 1000mm? If it's bedrock then you are laughing. Your you tube link says "this video is unavailable"

Do a basic financial plan. So you have a mortgage on the present house, but own the ruin outright. How much equity is there in the existing house.? How much do you think it will cost to build. then add a bit. subtract the equity and that is what you need to borrow, Living in the house next door while you build seems ideal, but can you afford that. Have you considered living on site in a static caravan during the build? I paid £10K in architects and engineers fees and thought that was a lot of "money for nothing" Don't forget there is no obligation to start straight away. Re group, work out your finances, and take time to plan what you are going to do.

Do it all with 2 port valves. So there will be 4 of them, HW to each house, and heating to each house. Each house can have it's own electrical controls and it's own programmer driving it's own pair of 2 port valves. Then when ANY of the 2 port valves is activated, the boiler and pump will fire up. How are they going to split the fuel bill for this arrangement?

I am sure the Scottish version referrs to general purpose. So what do you do if someone wants a wall mounted tv high up? Put the socket at 1.2 metres up the wall and have the cable hanging down to it? I don't think so

Only applies to general purpose sockets etc. Stick one high up the wall specifically for a wall mounted tv and it's okay. e,g I have a switched FCU low down so it's hidden behind the surround sound sub woofer.

Not so many people offer it, but economy 10 gives it's 10 hour cheap rate in more usable smaller chunks including a very useful afternoon period.

more like midnight to 7AM GMT varies a bit from region to region If you do switch to E7, then solar PV becomes more attractive as your generation will be offsetting the higher daytime rate.

The whole ceiling.

This is no different to wiring within the confines of a 25mm or even 50mm deep service void. As long as the cables are in safe zones, you have no issues. so just choose the wiring routes so they are in safe zones.

Assuming it's a typical Scottish 45 degree "ceiling"? Treat it as a wall, you will have a safe zone horizontally and vertically from every light fitting and 150mm from the corners.

Nice spot. If you have to do that, put them in a corner which will be in a safe zone.

I think you are misinterpreting that. >50mm or physically protected or in safe zone AND rcd protected. ALL of a ceiling is a safe zone, safe zones apply to walls. If you are really worried use perforated tray and set it >50mm above the ceiling. Don't over think it.

Starting at the right is my (now vintage) road bike that I have owned for 30 years. Then the 2 cheap mountain bikes that me and SWMBO ride, the purple one is our daughters bike, and lastly the folding one was given to us by a neighbour packing up to move out. Handy to take on the boat.

Meanwhile, inside the "Swiss Chalet" 101 uses for an old pallet. #72, a bike rack

What protection are you talking about? Are you trying to find a way to avoid the need for RCD protection? If so forget it. Just use perforated and rcd protect all your circuits. It is almost unheard of now to fit any new circuit without rcd protection. In any case the <50mm rule for rcd protection only applies to walls, not ceilings. It is to prevent damage from someone hanginf say a picture on the wall, something you don't typically do on a ceiling. Any cable damage during the build will be found on the final testing in any case. If this is not your reasoning, then what other 50mm rule are you referring to?

@JSHarris will hopefully see this as he has done this, and found it easy to get permission from the Environment Agency. It is a LOT harder in Scotland to get permission from SEPA.

The issue is not the panel weight, but the wind loading. A 4KW array is something like 25 square metres of "sail". A 2 axis tracker must take that and support it at a single point, and be strong enough that it does not break when that 25 metres of sail is subject to say 60mph gales. A bit easier is a single axis tracker where the elevation is fixed and only the azimuth adjusts throughout the day. You also need more space for a tracker than you do a fixed array, I am pretty certain I would not have room to fit a tracking array, I only just had enough room for a fixed array.

Here is a typical example, the first on I could find from a reputable manufacturer, not necessarily the best or cheapest, just an example. https://www.ebay.co.uk/itm/Samsung-Air-Source-Heat-Pump-5kW/223220316591?epid=19025583729&amp;hash=item33f8f7b9af:g:insAAOSw-pNb4eTC:rk:32:pf:0 They work best when you can keep the flow temperature low, say about 40 degrees. That will work well with under floor heating, but you can still use radiators as long as you buy ones designed specifically to run at a low water temperature. The principle of a heat pump is they extract heat from the air, so for every 1KW of electricity they consume, they will typically deliver 3KW of heat to your room.

Why unperforated? Standard perforated cable tray is available from electrical wholesalers, most will deal with cash customers, certainty CEF will, there must be a branch of them near you.

What make pump? I had a similar issue (different manifold) and solved the whine by changing the IBO pump for a Wilo pump

For the hot water, consider an instant electric water heater, or a low volume stored water heater, often referred to as "under sink" units. These make sense for low usage situations so you are not wasting heat with standing heat losses from water you will never use. And fit the largest power Electric shower you can find. Heat on demand but only when in use. Now you have separated heating from hot water, I really would look at a small monoblock air source heat pump. You can buy one new for about £2K or cheaper if you scour the likes of ebay for a bargain that come up from time to time. Couple this to under floor heating and you have a very eficcient system. Any half competent plumber and half competent electrcian can connect these for you. The high prices you have seen are probably from MCS registered companies trying to sell you a system that is eligible to claim the RHI, but often what appears to happen is their prices are over inflated, so your RHI payment barely meets the extra over inflated install price.

For me the solar PV was only viable because I got the price down by some patience and some luck. We have a burn, but there's hardly any fall. I think I calculated I might get about 50W from it. It might be a fun project just for fun sake but not a serious source of power.