Mr Punter

For a couple of jobs I have specced Weber LAC and mesh onto cement type boards, sponge finished then painted. 6mm thick. It has stood the test of time. Thin coat beads. Material costs are about £12/m2.

I have used Lead R which is a bit like flashband but tougher and a darker colour. Take your time to mark and cut the pieces and it should look OK. That flashband looks awful.

It it worth getting the cheaper ones for fixed and more expensive for opening? There is no rule that says they all need to be from the same manufacturer. Get them both to send a RAL sample before you commit.

What was the make and model?

PVC is fairly prone to discolouring. Front doors are normally fitted in the outer leaf of a cavity wall and the frame is sealed to the brick / blockwork. Without a sill, water should run down the face of the brickwork. It should not cause damp to invade! 22 years is probably not bad. I have paid £7,000 for front doors and have been very disappointed within 3 years.

Paving Expert has some advice. https://www.pavingexpert.com/setts05

If there are trickle vents and they are not closed they should provide enough fresh air. A dehumidifier is a cheap to run way of reducing humidity. Get one where you can run the condensed water to the outside via a hole in the wall and piece of hose, so you can leave it switched on. If the PIV is not doing the job, consider switching it off. Constant running extracts may work better.

MVHR will make no difference to overheating. The windows open give purge ventilation. MVHR does not. In bedrooms and living rooms it will normally just feed air in, not extract it.

With a pitched roof, most people either have a cold roof with insulation between and under rafters or a cold roof with insulation at ceiling level. It is unusual to have a warm pitched roof, with all the insulation above the rafters.

4m maximum spans are fairly standard with beam and block or timber joist. Any longer and the beams or joists get heavy and the floor can be more bouncy. With a crane, 3 people would be able to do the floor beams and blocks in a day. If you are hiring a crane, get as much heavy material loaded out as possible to make full use on the day.

If most SIP manufacturers think your roof is not suitable it probably isn't. Trusses or cut roof and maybe some steel are what is widely used. Who is doing the structural design? They should be able to help.

I like the island with no sink or hob. Great for serving up / parties and perfect for breakfast. Hobs or sinks on islands, especially with seating, are a bad idea. Unsightly and potentially dangerous. I rarely transfer stuff from the oven to the hob or vice versa so the distance would not bother me. If the tall unit next to the oven is a fridge freezer I think it looks small. I am putting a similar integrated fridge freezer in a 2 bed flat. Your place looks bigger and you may like more fridge space. I don't think the bench seating will work. OK if it is a banquette or booth to seat max 6 but this is much too big to sensibly use. Using them for storage will be a PITA and they don't look comfy for a leisurely meal. I don't like an oven next to a fridge. One heating the other cooling. I love the windows but be wary of echo / reverberation which can be quite grating. If you have space elsewhere in the house for the TV it may be better. We don't have one in the kitchen / dining and it means we tend to interact more.

I am a big fan of dehumidifiers. I would suggest getting a couple of Meaco units, piping them to the outside with a bit of garden hose and leaving them on constant. They running costs for the pair should be about 6p per hour. You can dry your washing indoors without any issues.

It looks like they built it overhand as they did not have access. When the fence is down they could point it up or render it if you allow them access.

The kitchen layout is not good. Maybe get a design done. The new cavity walls wrap around a fair bit of the existing which reduces the EWI a bit. You need to make sure the left hand gutter and roof does not overhang the boundary. That is a hell of a lot of work and a pain if you are living there. Have you priced it? If it works for you, get it done ASAP or the kids will have grown up before it is complete.