Mr Punter

Be very careful with your wording. Terminating the contract brings to an end all obligations from them. If instead it is Determined, they may still have liabilities such as defects etc. Be careful here as either way this could trigger legal action and it it very easy to get on the hook through a technicality.

Could you fit any external perimeter insulation? It would involve excavating a trench around the house and filling with EPS insulation. It could marry up with your proposed 200mm EWI.

Did the neighbour get trapped under the soon-to-be falling mixer? 34 years on and the paving still looks good. The pictures are a tad homoerotic, but that was standard back then.

@Conor did a walk out basement in ICF.

Are we too late to suggest getting rid of the timber floors and replacing with an insulated concrete floor with UFH?

Basements really can be a huge challenge. The more underground, the more problematic.

If you have several to do, the glazing robot sounds a good idea. You may need to spend a while prepping the ground.

You could fit a bidet. Not fashionable here, compulsory in several European countries. Easy to freshen up without getting undressed.

MPR / OCR is good stuff and can be painted. Rendaid is very good as a base coat for poor or mixed backgrounds and is very sticky.

I don't think you can still get imperial sizes in plasterboard.

Anything that sticks will do. Masking tape, gaffa tape. Just to stop getting mastic on the stone as it is difficult to clean off.

You may need tissue faced insulation but it can be pricey. It may depend on the membrane.

If the gap is deep, push in some foam backer rod so it is set back about 10mm, then use a joint sealant like Sikaflex EBT+ from a mastic gun. You will need to mask the stonework. It isn't the easiest to finish but does a good job and stays flexible.

The preference is to keep all the timber on the warm side of the insulation. I would go firrings on the decking, then another support layer of decking, VCL, insulation, waterproofing, sedum system.

Some closeups would be useful. I can see a tiny hairline crack in the padstone and the first mortar bed but not much else. It looks like this is a junction with another wall so you may have a few more perps than otherwise. From what I can see, nothing to see. Unless the padstone is taking an unusual load or on on the existing / new junction, I would leave it as is.

My final attempt:

I drew it. I am shite at bricklaying though.

Like this? Cut block are coloured. Flat blocks laid mum and dad. A bricklayer might have a better idea though!

£298. Discharge all of them at once.

Can you screw a metal angle to the back of the threshold that rests on the top of the concrete?

You can run your pipe as steep as you want. 1m depth really is pretty shallow. Ask Thames Water, but a 1m trench is not the end of the world.

I hope the developer is well funded. Have you checked their credit rating? Often the warranty firm will go after the developer to get reimbursed. Some set up a SPV with very little capital. Is this a warranty claim or or against the developer or both?

I don't think the adhesive is critical for this. Just pour the beads in.

It looks like some of the board was used in the outer leaf!