Mr Punter

As long as the revised plans address the reasons given for refusal you should be OK. If you have gone through an architect I am surprised they were not asked by the planners to make some changes, rather than a straight refusal.

A concrete lintel may be simplest. The height of the lintel depends on the opening width. They tend to be the equivalent of 1 or 2 bricks high. You can just sort out the arrangement of bricks to suit the height you would like the lintel to be set at.

I have a fan mounted remotely which is quiet and effective. You can get weatherproof ones as well that go on the outside wall.

You can either use a core drill with SDS or just break out a hole big enough and foam around and fill with sand cement.

You may need a bit more insulation as well. I would be wary of timber cladding on timber frame for insurance / mortgage / resale reasons. The Cedral / Hardie type stuff can be a better bet.

Zurich are a very large and well regarded insurance firm. In my experience, none of them will pay a claim happily.

Mahogany and Satinwood have traditionally worked well but I imagine they are not on the menu. Not sure of your budget but I have seen some fantastic reclaimed parquet type flooring. Probably well over £100 / m but it would look fine with other wood furniture. I don't think wood "clashes".

It is sometimes a good exercise to draw in where the airtight layer will be, then consider how it will work at all the junctions. Your airtight layer could be polythene or plaster but it really needs to be contiguous. The first option looks easier to achieve for insulation and airtightness. The bottom one looks pretty flaky.

Remove the bottom row of tiles and fix a board to this. Run the roof covering up the board under the tiles. Ideally your flat roof insulation should be going on top of the rafters so you may need to strip 2 rows of tiles.

I am not clear on how it would be possible to install a cavity tray in an existing wall, other than when the wall is opened up and a cavity tray is put in above the new steel. Anyone?

Why does this ceiling need to be airtight? For sound attenuation, the walls will make no difference. It is the sound vibrations from the floor above that you are trying to minimise. You also need to avoid flanking sound through gaps between the ceiling and the wall, which is what the mastic and plaster will do.

Why don't you install an external staircase then just carry the stuff down...

It is well worth getting an actual sample of the materials and looking at them together. Mostly they will send them out for free, but even if you have to pay it is worth it for the peace of mind. I find it surprising how long someone will ponder an item of clothing or a duvet cover yet go for external materials on a house they have not seen.

No you definitely need an electric one. Like this https://www.hss.com/hire/p/htc-gl270-grinder or https://www.hirestation.co.uk/tool-hire/Building/Floor-Grinder-Hire/130040/

You could use a zipped standing seam like Kalzip or Rigidal. They do roofs for huge buildings. You can just have a big gutter at the back with, say, 3 downpipes. I have used these on a couple of projects.

Sheet piling you could cut them in half and push them in with a digger bucket. They would be strong with the corrugation.

They are not different types of roof, just a different way of securing the ridge tiles along the top. The rest of the roof is exactly the same. From the ground it is difficult to tell which you have. The big difference to how the roof looks will be in the type of covering, where large format concrete tiles will look more modern than, say, clay plain tiles.

I often see it with the breather paper. I am not sure why though. Also it may make fixing the battens difficult if it tangles up on the drill, although with light blocks you could nail the battens.

This seems an area of confusion. I have an architect who insisted that the steels were painted, even though they were protected by the ceiling. They then went on to say that unless we accepted the intumescent paint we would need to prove that the steels were protected from fire including from above. There is basic ignorance abounding with this, among architects and building control. I can see just why Grenfell happened. In reality if you try to apply intumescent pain on site the steel will go rusty and you will not achieve the correct thickness. It also needs a clearance all round to expand.

The brickwork above the shit brown window on the ground floor looks knackered as well, but again, not fatal.

It is down to technique. For the upper floors, can you get a telehandler to lift a pack up so you can drag the sheets off? You may need the scaffolding gentlemen back to help improve access.

15mm board on ceilings with 600mm centres please. If you don't, it is nog-tastic.

A lot of that is where the edges of the trowel have extra water. Check it with a straight edge. Give it a coat of paint.

I have worked with similar and when we did the back garden I had to 'modify' a couple of wheelbarrows with a lump hammer to make them fit the gap.

The dry rot does not destroy brickwork but can travel through it, eating up any embedded timber. I would walk away form this. It looks cheap because it is potentially a money pit. Dry rot, damp and subsidence are not simple to remedy, especially when you are not experienced. Avoid.