JohnMo

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.

Background to ventilation Uncontrolled ventilation is leakage of the house structure - you can ot change it it's built into the building fabric. Controlled ventilation is ventilation you can control, increase or decrease. Basic, leaky house, no trickle vents are needed, an intermittent fan in bathroom and kitchen via a cooker hood. The combined uncontrolled leakage and a little controlled leakage gives satisfactory ventilation. Most your ventilation is uncontrollable leakage. As you become more airtight you add trickle vents to dry rooms and either intermittent or permanent running fans to wet rooms, these again give ventilation, the tighter the building becomes the more you move towards permanent running fans. You still have a decent proportion of uncontrolled ventilation though. MVHR needed for good air quality in sealed houses. But not the only solution. Here you almost have no uncontrolled ventilation. MVHR in a leaky house. The house will still leak air in and out in an uncontrolled matter. MVHR will add extra ventilation on over and above the uncontrolled ventilation. Net result is way more ventilation than you need, and additional ventilation heat loss. Maybe too dry an atmosphere in winter leading to dry skin etc.

We used 45 square unistrut for ours. Hot dip galvanised. Ring around, as price vary hugely. Ended up paying less that half the cost of my first call to local electrical wholesalers and had 6m long lengths delivered free.

The general consensus is airtightness better that 3m³/m² at 50Pa then MVHR can be cost effective, once installed. If your airtightness is worse than that it doesn't pay you have it. The most silent dMEV fans I have found are Greenwood CV2 or CV3. The CV2 is generally available on eBay pretty cheap. With MVHR or dMEV you need to make sure your doors internally are uncut about 10mm to allow between room ventilation. All dry rooms need inlet ventilation for dMEV to function correctly. If you have dMEV or MVHR then venting out cooker fan isn't needed. Just add a carbon filter and let it recycle the air. The MVHR or dMEV will get rid of any humidity, the grease and carbon filter will go the rest.