Mr Punter

Charlie DIYte did a decent review of plasterboard fixings. Insulated plasterboard at about 25 mins in.

You need to see what the fire service want. Can you improve access? They will sometimes concede a bit and relax their requirements.

The first layer you could do with blocks but you won't have 50mm. You can get concrete block spacers. Second layer metal deck chairs tied down. Shop around for prices.

Torch the house and use the insurance money to get a house with proper drainage.

This is Canadian Western Red Cedar untreated, 15 years post installation.

You can get adapters for clay to plastic.

Still a few bits to do. Looks neat enough to my untrained eye. Can you get the chimney in pic 1 pointed while the scaffold is up?

Yes you can build over them. You may need some access, like a sealed lid inspection chamber depending on the pipe runs. Not an issue with carpet or vinyl as you can relay. Tiles can be accommodated almost invisibly. Timber floor you will need to get it fitted to allow for access.

A friend who does gates and access often suggests wiring for a socket at the gate end. I think it is so he can plug in his charger and make tea when he comes back to service them!

Concrete blocks or medium density aggregate blocks will be much better than Celcon.

Don't go deeper than you need to. I have had 150mm cover on drains near to the building. Would need a bit thicker with RC capping if under a driveway.

The way the manufacturers show the rigid full-fill insulation is a world apart from how it goes in on site. DriTherm or blown poly bead with a wider cavity may be better.

Is this confessions of a Tory Minister?

Get some quotes at a very early stage and work out what is feasible. You need to double your budget or halve your expectations or a combination of both.

I may be missing something and am no sparky. Where is the issue with the existing setup? If the cables are in decent condition, securing to the joists with some cable clips will keep them off the soil. Why spend money and resource stripping them out and replacing?

Why not just leave the ducting up there and top up the insulation? The ducting is plastic wrapped and insulated with glass wool, so is safe to leave.

100% knock down and rebuild. And get a price for the staircase before you entertain the idea any longer. What is your budget?

Very odd but at least you got the required consent. Hopefully at not too much cost.

Clipped to side or underside of joists is fine.

No. It looks like glass mineral wool insulation.

I am with @DevilDamo. Just get some plans drawn up and submit them for planning. PD rules don't apply for you here. If it is well designed and attractive there is no reason it should not get consent. You won't be listing arguments in the application, just decent drawings and careful selection of materials. I have known planners turn down PV in a Conservation Area.

It is probably B785. Never used it myself. The B meshes have different gauges and spacing of wires, so I imagine they should be placed in the correct orientation? It will be heavy and awkward to handle.

Get ChatGPT to draft a response and post it up here.

Ask the SE to just do 100mm concrete slab onto compacted MOT. Why is it reinforced? You can then have insulation and 50mm liquid screed or 75mm traditional screed.

Materials alone will be an extra £150/m2.