Mr Punter

Plastic inspection chambers are not designed for steep gradients so you may need to build one to suit. Talk to your groundworker and to BC. What depth is the pipe?

A friend does automatic gates and access control. He cuts a wire loop into the driveway which seems to be a favourite. Why on earth would you want to tie your automatic gate functionality to a particular manufacturer?

+1. May as well heat it with the car exhaust!

Why not just shift the fridge elsewhere in the kitchen, tile where it is to go, then move it back?

Agreed I have heard this claim but cannot see it in the Building Regs.

You will need mechanical ventilation in the kitchen, bathroom, WC and utility. You also need trickle vents to all the habitable rooms. The fans may need testing also. What did Building Control put on their Plan Check report?

I like traditional sand cement screed. 75mm is quite thick for liquid screed. If you go liquid, use Cemfloor as there is no laitance removal needed. I have used Sigma Screed in the past and they were very good.

I think you need check reveal cavity closers as one of the wings will clash with your brickwork. These https://insulationgo.co.uk/150mm-xt-cl-close-r-checked-fit-pir-cavity-closer-brick-outer-pir-core-insulation/ or if you want fire rated, which may be a better fit with the rigid insulation: https://www.insulationsuperstore.co.uk/product/arc-ecocloser-150mm-fire-rated-cavity-closer-2-4m-length-pack-of-6.html

I have one in a student HMO. I have also had the undersink type with storage in an office suite. Neither property has gas. I don't think I would want one at home.

Strip the roof and re-lay. You need MINIMUM 50mm into the gutter. They are fibre cement slates fixed with nails and disk rivets. You could sort out the rest of the woeful bodges while you are at it.

I have done similar using resin anchors to face fix a timber ledger to the wall, then timber to timber joist hangers for the joists. It means you have more freedom in floor height and better airtightness. Your blocks should be fine for this as the ledger will have fixings every 400mm. Cleaning the drilled holes with brush and blower is key to a very strong fixing.

I would just go ahead and do a retrospective if it crops up.

Don't pay them until they get it right.

A more important factor will be the loss in floor area, which if it is 1.9% on a floor area of 160m2 would be about 3m2, which could be worth between £6,000 and £12,000 depending on location.

I have had quotes for this before and they were very expensive to cover the whole house, but can be handy for smaller areas. Get a flow rate / pressure check. You can request a very meaty supply from the water co. just for fire sprinkler purposes. Have it separate from your main supply.