Mr Punter

Forget the readymix, just a couple of tonne bags of ballast and 12 cement needed. How is the rebar fixed to the posts? Make sure it is 32 or 40mm. Ducting between posts for automation. Be good if the posts were galv.

It should be fine to walk on. A dry ridge / hip setup may have been better as it does not rely on mortar joins. Maybe the battens and / or rafters are rotting? Can you see it from the inside? Any daylight?

If you submit your appeal near to the 6 month deadline it will probably be over a year until the Planning Inspector sees it.

There are firms that will cut and bond the bricks to your spec and not a huge lead time.

I think A looks better. A very well fitted VCL under the joists will prevent warm moist air getting into the roofspace. Don't ruin it with a load of downlights lashed in.

You could do external wall insulation and painted render. I think it could look good.

If you have a properly designed and installed type c drained cavity waterproofing system the room would be dry. It requires the membrane on walls and floor, a perimeter chanel plus a sump / pumps if you cannot drain via gravity.

Use concrete blocks to hold down wide DPC over the cavity. It will all dry out eventually. If it got really soaked, could you drill a few holes at the bottom of the wall?

Larger sand content will help it drain, as long as it doesn't form a sump you will be OK. Backfilling with clay is tricky as it does not always want to compact nicely. You could end up with a 30cm strip of bowling green lawn!

I have some flats in Conservation Area. All electric mostly small single occupancy. The EPCs are confusing. The top recommendation is internal or external wall insulation at a cost of £4,000-£14,000 each. With the lower figure it would take 30 years to pay back, with the higher figure 106 years. They liked to recommend high heat retention storage heaters and dual immersion water heaters. The flats are mostly D and E. One from end of 2019 recommended gas boiler. Most are out by a fair bit in floor area. Pretty crappy system IMO.

It would look neater if it was filled and painted but it shouldn't hurt as is.

Can you put some compressible insulation around the pipes where they pass through the 2 layers?

The cost for heating and DHW for a 5 bed house are fairly small compared to other costs, like mortgage, school fees, holidays, pensions, food, travel / car. Maybe energy costs on a crap house is £4k a year and a good one is £1.5k. On a £750k purchase it is not such a big deal.

No photo of the gable end so we were not fully briefed! I take your point though. Chimneys, fireplaces and chimney breasts are often focal and are an attractive part of the character, especially of period houses. They are also impractical and largely redundant.

Sharp gritty aggregate and well rammed in or even MOT type 1.

Take it down and roof over it.

You probably don't need 50mm service void and you could go for 25mm or 38mm. Ditch the Fermacell if you don't want a fight with the sparky and plumber and plasterer and labourer and bank manager.

Modern softwood can be fairly crappy in comparison.

Cheap softwood windows can rot through in no time.

I am surprised they are not fitting a meter when they change the pipe.

If those pipes are connected to a saniflo you got what you deserved for dining with the Devil!

If this is an old property with not much floor insulation the tiles are going to feel really cold.

I prefer to build, then sell. The only choices the customer gets are carpets and I don't do those until contracts are exchanged. That way, the customer can take their time and make sure everything is OK. Don't mention the prospect of another plot, just sell the one you have for as much as possible. That will save any grief from timewasters.

Not sure if it is the same for self builders but if you detail planting and landscaping as part of your planning consent it may be eligible for VAT refund.

You can get shower valves for when the plumber has mis-piped the hot and cold. I think Grohe do them. https://www.showerspares.com/search/grohe_thermostatic_1_2_compact_cartridge_reversed_inlets_47175_000/