Temp

Wherever you go its worth discussing the grade with the company, possibly even testing a sheet. Some of the WBP out there is worse than Wheatabix in hot milk

Perhaps check that the cold supply to the house can deliver enough for 2+ showers at decent pressure. Then what @SimonD said. Think you will need a decent sized tank.

Didn't they take pictures?

That appears to assume you will be paying VAT on everything including labor? Labor should be zero rated to you, cannot be paid and reclaimed. You only pay and reclaim VAT on materials you buy. You might still want to apply for nearer the £462k mortgage though to give some flexibility if costs over run.

No not unless the corner is just a small pillar between two large doors

No don't think AAV are rated for outdoors. Normally if you can get the vent pipe outdoors you can get it far enough away from windows that it can be open vented. What you have drawn on the right is fairly standard. The short/stub stack and AAV are either boxed in in the corner of the room or sometimes a concealed cistern is put in the boxing as well. Our house is a 1&1/2 storey house with bathrooms in rooms with dormers. In one room we have a Geberit concealed cistern in the same boxing as the stub stack and AAV. The WC pan is a floor mounted back to the wall design. In another similar room we have a Geberit frame with integeral cistern and a wall mounted pan.

Think we have a similar situation. Our extractor is a bit narrower than our Britannia 100cm. Doesn't seem to be a problem as long as the canopy itself is high enough across the full width to meet Building Regs which it sounds like yours is.

I can't think of a reason why not. Provided it looks like crushed rock rather than rounded river pebbles. Probably safer to use it under concrete floors rather than in the bottom of foundation trenches? I'm not an architect or structural engineer though.

We have something like this (not my drawing). Any "steps" must be less than 12mm I think. I think our concrete sill is flat topped (no tiny step as shown below) with a 12mm high aluminium extrusion on top that the seal on the bottom of the wood door mates with.

You might be able to replace the left hand side and the vent with an Air Admittance Valve (AAV) in the bathroom on the top of a short stub stack. This should be higher than the wash basin overflow. Can be hidden in boxing but should be accessible in case of maintenance. Building Control normally prefer one open vented stack like you have now but don't think they are mandatory any more. They used to insist you had one open stack but any others could have an AAV.

Anyone know if the MK 32A cooker switch still uses a neon or is it an LED now? Every where I look it says neon.

Just a reminder that labor on a new build should be zero rated for VAT to you. Not charged and reclaimed.

full demolition allow you to get the whole project zero rated for VAT

Did you ask them to quote including installation? If you did then I agree this is a bit odd. My guess is you didn't so they are just trying to up-sell you some sealant. Whoever is going to install them will have their own preferred make and method so I'd probably decline the silicone. You can buy the stuff everywhere. Does the quote have the right VAT rate... If the quote did include installation I believe the whole thing should be zero rated for VAT to you. So check if the quote includes VAT. If it does then you need to tell them its for a new house under construction and should be zero rated. Supply your planning reference number and ask them to requote. If it doesn't include installation the quote should include VAT which you reclaim when the house is finished.

Our close trees have never been a problem.

Only the BCO signed our completion certificate.

Everything emitted by an electric heater ends up as heat in the house. That includes the sound from the fan and the light from the led (well unless it escapes through a window). 300% refers to the COP of a heat pump and they can reach over 400%. Ok so technically COP and efficiency aren't the same thing but for practical purposes they are.

Interesting thread.. https://customerhelp.landregistry.gov.uk/forums/general-info-and-guidance/6ab2b443-137d-ef11-a4e6-6045bdf15e68

As I recall it's to do with covenants but if there aren't any perhaps it's not a problem for the Land Registry?

There are quite a few programs that can edit embedded data. Think some can change location data. Perhaps try something like EXIFtool? Obviously work on copies to keep the originals unmodified.

Can be an issue with the land registry if both parts are in the same name. Something about covenants not being enforceable against yourself? I forget the details.

That's good because I think if it had to be "incidental to the main house" a bathroom isn't allowed. I'm reasonably sure Part M won't apply as its ancillary to the main house not a new dwelling. If you decide to ask Building Control I would emphasise that.

Is there a planning condition requiring it to be "incidental" or "ancillary" to the main house? If so which?

What's needed is a big enough bore overflow from the butt back into the drain. No need for diverting switches.