Planning decision notice and general drawings, I sent floor plans and elevations. They just need something to verify that you have permission and rough scale of the development.
Other way round, I have windows in RAL7015 Slate Grey and was looking for matching profiles etc. Found BS18B29 a close match but depends on product, surface finish and manufacturer.
As above, depends on the MCS installer’s calculations … which depend on assumptions made. You certainly don’t need UFH upstairs but the calcs may show the need for some heating in the bedrooms. I went for (wet) towel rads in the bathrooms and radiators in bedrooms, were quite cheap to install but rarely needed.
I also tend to avoid the latest fads. My first house had open fire places in every room and leaky sash windows, plenty of fresh air without any fans. Now though, with modern standards of air tightness and more concerns about VOCs, CO2 levels etc. active ventilation is essential for most new houses.
I agree with your comments about passive cooling. MVHR doesn’t help much with cooling but has so many other benefits and it is not necessary to spend £12k. I self installed this unit and spent another £1k on rigid plastic ducting and other materials. Of course you can spec something more sophisticated but this works very well and I wouldn’t want to live in a house without MVHR and I don’t want people to be put off by these quotes.
https://www.ventilationland.co.uk/en_GB/p/itho-daalderop-mvhr-hru-350-eco-unit-lr-rft-low-rise-350m3-h/9945/?gad_source=1&gad_campaignid=22563121607&gbraid=0AAAAAB0qKPDJ-kmgBYRAOrw1rwDPtmlOW&gclid=Cj0KCQiAiKzIBhCOARIsAKpKLAOKcw9T7CHFnPu-qqBlrN6gM85GPOdAMbqVvfGZpXWti5CANHf1dMwaAjWTEALw_wcB
Yes, trades must invoice zero rated for all labour and materials. You can buy materials and reclaim VAT as long as they are on the eligible list https://www.gov.uk/guidance/goods-and-services-you-can-claim-for-under-the-vat-diy-scheme
Your accountant is talking nonsense 🙄
I think it looks better with different wall cladding to the roofing material but that’s just my personal preference. The slate roof will look absolutely fine and will be much cheaper than zinc.
I agree the entrance elevation looks a bit odd.
Do you have a drawing of this arrangement? I think it would look better with the same cladding to ground and first floor. Also the same width, don’t know why the first floor is the same width as the roof?