JohnMo

Run it like a proper contract. Weekly progress meeting and minutes taken with actions and agreements stated in black and white. You discuss work scopes and money. If the workers are not there half the time, ask yourself and the builder why aren't they. You should only have about 10 to 16 weeks work to do, from the scope you described depending on house size.

You just need to keep simple, otherwise you will procrastinate and never get any generation up and running.

Why not use mineral wool then zero cutting?

Check the diagonal dimensions to make sure it's square, you have nice oblong building so should be easy to get right, but ...

Trouble is the ideal angle really changes on a daily basis, even an hourly basis if you wanted to be really fussy. I just have around half my panels at 45 degs and the others vertical. Also have 2 set horizontal and they generate nothing mid winter. Complication added, really depends on export limits if it worth changing angles (and if you actually get paid). We are limited to G98 exports, so even in February we get plenty of clipping in the middle of the day if the battery is already fully charged. So no benefits for me, having the complexity. Simple fit and forget

Only if your flow temperature is stupid high. Long outdoor pipes benefit from lower flow temperature, aim for a max of 35 and you will be fine. Then you will be fine with 25mm insulation.

My heat pump is behind a shed and pipes go underground to the house. No real need to go next to house. But the units mentioned by @DamonHD and similar units would be a super easy swop, no plumbing to do. Concentrate on downstairs rooms and maybe panel heaters in bedrooms or leave the storage heaters in those rooms.

So we are talking £600 in panels, plus mounts. Couple of hundred for an inverter? Solar is still pretty cheap at the moment, getting more expensive by the day. Buy don't faff

What outdoor space do you have, garden etc? Flat roof?

Good luck - can I ask why?

Or just do an ICF, stack the blocks fill with concrete, U value 0.14 with service void. Parge coat for airtight if woodcrete, no need with polystyrene blocks. Our house, 4 weeks (end Nov to Christmas, bloody freezing) 70m perimeter and average 3m tall, two of us never done it before. 2 days to parge coat internal wall.

Think that 33% more complex than you need. Stud plus internal OR external, NOT both

Do you need the internal breather membrane? Cannot see what that does. Between studs knauf Frametherm 32, easier to install and better U value. I would do a simple twin stud, fill with frametherm 32, or blown in insulation. OSB board outside with membrane. Or 140mm structural, OSB outside with membrane, internally PIR skin over studs to achieve u value

Are you seeing any issues yourself?

Don't overtighten fitting with olives.

That really doesn't mean it complies. If you structural engineer says nails, that's what your structural design certificate covers. If you want hooks, make sure the structural engineer is happy. Pretty much don't comply with any of that. Full fill Icynene, open cell foam. Proctor Roofshield, so a very open membrane. Full double taped vapour control membrane and service cavity inside house. GSE trays have plenty of air channels to allow ventilation. When generating plenty of thermosyphon driven ventilation also.

We did integrated solar and slates. The solar trays are screwed directly to sarking. The slates are copper nails direct to sarking. Breather membrane on sarking boards. Slate hooks, do they comply with the Scottish wind loads?

The sarking boards do that, with the breather membrane. When they fully dry there is a gap between each board. Not sure why the architect has shown battens on the sarking, with real slate they are not needed.

I would push back on 170mm kingspan between rafters and use a more flexible and very easy to correct mineral wool, something like Rockwool Flexi. Do it thicker to to U values. Same for walls, but you may need to increase the 25mm inside to something a little thicker. Back to your question, it looks fine, well protected. On your 1st floor joists you may need to be wrapped to join the 1st and 2nd floor wall VCL to join.

You have the issue if cutting in and getting nice crisp lines. But if your not really careful with colour choice, the walls may just look mucky. Just do one white everywhere.

I would go back to you planning approval notice, it should state exactly what documents they need for sign off. Our didn't ask for and didn't receive anything for windows and doors.

Contract warmcell, they are a distributor/ installer company. Also look for THERMOFLOC.

That the joy of owning a listed building - don't want to play by the rules, don't buy listed. Don't confuse planning consent, with listed building consent. You need both. Planning consent is easy, list building consent will turn you grey especially if you don't want to play by their rules. There are ways do things and do them well and still comply with listed rules. But you need to keep the listed folk on side. And have deep pockets.

I wouldn't bother with the MVHR unit you propose but install one of these in you kitchen, utility and bathrooms https://ebay.us/m/ROuJpj If your dry room windows have trickle vents replace with these https://www.shop24glasgow.co.uk/en/search?controller=search&s=AERECO If they don't have install something like this https://www.heatrecoverydirect.com/products/s-p-em-hy-humidity-controlled-air-inlet-install-100mm?variant=49866952540487&country=GB&currency=GBP&utm_medium=product_sync&utm_source=google&utm_content=sag_organic&utm_campaign=sag_organic&gad_source=1&gad_campaignid=22034401125&gbraid=0AAAAApOCirjcUNbeNqKiRFAf35BF6ArLV&gclid=CjwKCAjw687NBhB4EiwAQ645dsrORFKnBkTQ2Q9IRY8v-_DuJgE6HbJuPLAFz-T3LlMUipNQsgvICRoCNUwQAvD_BwE Then you will a humidity sensing ventilation system

Then try to find some cheap heating oil.