Mr Punter

If you have a large amount of solar thermal gain I am not sure that cooling the slab will make a lot of difference and it may feel uncomfortable in the evening and morning. Can you not apply solar film to the windows and control the issue at source?

If you place timber into concrete and you want to remove it, cover it in clingfilm, as otherwise the timber swells and is "tricky" to remove!

Yes, frequently jetwashed. Sometimes scabbbled as well to expose some aggregate to act as a key.

What if the property is completed, occupied and not on the valuation list? Can they add it to the list and reclaim from when occupied?

With a turd popped in for good measure (and for real world accuracy)?

The front door threshold will be level with the adjacent ground also.

BTW anyone know which approve document covers this?

This type of reg really annoys me. The idea is to stop liquids from the garage getting into the house, but is that really likely? A simple threshold of 30mm would easily do it.

This is no longer considered the case. There is no evidence that solids get left behind and so there is no maximum gradient.

Easy enough to get planning then find you need bigger joists, taller roof buildup or whatever. 30cm and they would probably have been OK, but 30 inches was no mistake. I wonder if the building is taller or just not set down enough - the drive slopes up a fair bit. Either way they are screwed.

I looked at a similar comparison before but you will need a 150mm cavity to get similar u values, so wider footing and smaller floor area. We used Celotex full fill boards - they are currently suspended from sale. The Kingspan looks a pain to work with. How you are supposed to maintain a 10mm residual cavity and tape all the boards is beyond me. Probably never happens on site.

I think the decking will rot pretty fast. Compacted sand would be better.

Worth checking how high above floor level is the horizontal as you need to consider safety when opening / cleaning. I don't see that the windows either side of the double height need to match it, but they will probably look better matching each other.

If they come back with a defence it would be worth you downloading some design details from other suppliers or walk on rooflights where their drawings concur with the way you measured. If more than one firm has your method as a standard, I would think your chances of of success would be greatly strengthened. You will probably need to submit these to the Court and the other side before the hearing. Also, did you get quotes from other firms and if so, what was the basis of their offer(s)? Again, if you can establish that everyone else used dimension X and the other side seemed to use dimension Y I think your case will be strengthened, particularly as you are an individual consumer so there is no presumption that you should have known better.

Agree with @Russell griffiths that 1200 is minimum. Any eaves / gutter overhang or is it a gable?

A knowledge of the ground conditions is a must. Also, is the basement far from boundaries, which will make excavation simpler? What is it to be used for? Does it need drainage for WC etc? Any light wells? If you look at the construction cost per square metre of basement being 1.5 times that for above ground and factor in that the end value will likely be 70% of the above ground, does it look viable?

I don't think it looks attractive. What is behind the design? Is it to follow a local vernacular or a certain style or look that you aim to achieve? You will be spending a lot of money and time building this, so it will be worth paying to get a couple of professionals to come up with some ideas, as you risk it looking a bit "nothing". As with @ProDave the dormers are a no-no, as is the arched window and the Georgian windows. The outside needs to be properly resolved.

Unless you are building over a swamp you are being paranoid unnecessarily cautious.

As long as it has manufacturers accreditation (BBA etc) for this there is no problem.

Do it from the inside later.

Concreting looks straightforward but is one of the most exacting things on site. It is very easy to mess up and timing is crucial. Check out @PeterStarck's blog https://forum.buildhub.org.uk/blogs/entry/73-now-for-the-foundations/ Most sites the contractor would get away with this and it is probably only becase Peter was meticulous that he didn't get flannelled into accepting a cock-up. Good to see you checking levels at each stage - not just assuming that the next layer will compensate. Give yourself a pat on the back. A fantastic job.

And in the rooms...

Some pics

I would go for running 2 anywhere you are likely to use a tv, computer, printer or phone. Run back to a central location where you also have power. I terminated them into a couple of 8 port Trendnet patch panels flush mounted into the plasterboard and connected up with patch leads into a 16 port gigabyte switch. I went for a fanless one as it is a wardrobe and I didn't want any noise. Also ran all the tv coax to the same location. It is a bit of a cable fest, but it works well.

It would be up to you neighbour if they choose to consent to you building on their land. You have shown this as a solid wall but it will probably be a cavity wall so may step in a bit more. You would also need their consent and an easement if you have any gutters etc. I don't know how option 2 would work as you would need your roof to cover the new wall, unless it is built as a parapet.