Conor

We had a similar issue with a door frame. We didn't want the faff of removal and waiting months for a replacement, so we compromised and they sent somebody out to spray paint the inside. Flawless and you woulnt know the difference unless you got down and had a really close look. Start thinking along those lines and what compromise you might be willing to meet. As above, all comes down to the spec / order sheet you signed. our window were very thorough and clear in this regard. Had a simple one pager with the big items like quantity, colours, spec, and then a full booklet with the extreme details of every individual unit.

A better way to do it is to aim for a total heat demand / load per m² and make sure your build hits that through design choices and build quality. E.g. PH standard of 10W m² and take if from there. Decide what you want from your house, how you want it to feel and perform, and design accordingly.

What's in the cavities? Have you checked? And as Redbeard says, you want 400mm in the loft. It's by far the easiest and most cost effective way to improve insulation in the house. A few have mentioned drafts, but if you have condensation issues, im not sure that's a big issue.

Make sure the foul is the lower of the two pipes. Check the building regs, for pipes that shallow you might have to cover in concrete. Paving might not meet the needs.

This will be one for insurance to sort out. Definitely don't start ripping stuff out. Make the notifications, kick up a fuss, but don't put your hand in your pocket.

Your fridge will make up the shortfall.... And remember that shortfall is on the coldest day of the year. And you've other heat sources in the house, and air movement from other areas. It'll be fine. Move on to the next job.

Stop the leak and park a dehumidifier there for a a few days. Quite possibly do more harm than good lifting the boards.

You assume the role of PC. Just update your documentation etc.

Thick carpet and underlay are your friends here. Job will be done and dusted this time next week and your house will be warmer for it.

We've carpet, towels, LVT and 14mm laminate. All works well. Apart from the but under the 1" thick wool rug 🤣

A weed membrane will stop the roots of any weeds getting down into the soil. But, by that point the plants will be big enough to be a nuisance anyway, so not a huge benefit.

Pipe needs to be straight and not pulling, these things leak easily, I've installed 100s of them. Strictly speaking, this is the property of the water company and you shouldnt be touching them, better option is to call them and say their meter box is leaking.

It'll just be an old clay pipe running in to a ditch. If in doubt, budget on a full new treatment plant and soak away / discharge and get it taken off the asking price.

Unless you were face into it with a grinder, drill etc with dust flying everywhere, there's almost no risk.

Only way to know is to get a sample tested. Plenty of companies offering that service. May as well do it and know for next time. But if it's all now sealed / covered up, then there is no point going back in at this stage.