Mr Punter

Another vote for 1 then

I would prefer 2 x shower rooms en suite and 1 shared bathroom with bath and shower. I think you could have a re-jig. Can any en-suites go back-to-back? May be simpler to plumb. What is the small internal room 2.7m without a door in the first one? If you got rid of it it may be a nice space for desk / sofa.

Why not offer your neighbour £500 if he agrees to the work without a Party Wall Award? I have to do some works that fall under this and there are 4 neighbouring properties. I am tempted to offer the cash to them.

Afraid so. He doesn't even need to object, just not agree or reply. If you can both use the same surveyor the fees can be less.

They will still be counted as foundations and will not be treated differently. I know it will have no effect on your neighbour's property, but it is the law. Originally for tight knit housing in London it has been adopted for the whole of the UK. A nice earner for the surveyors. Get a price from them first.

No real choice I am afraid. I don't know why people think it offers them any protection. I guess at least the job has been looked at by quasi professionals and an award produced. If you go ahead without a Party Wall Award or agreement from the Adjoining Owner he can opt to seek an injunction. It is fairly costly for him to do but if he succeeds you are stuffed. Judges take a dim view of Building Owners ignoring the Act. It doesn't really matter how deep his foundations are unless his are also piled. If you are piling within 6 metres you need to follow the Party Wall Act. As a P.S. In the past I have just gone ahead in the past at the risk of being injuncted. I guess they thought they had more to lose if they failed in court so they did not do it. Piling was done in a couple of days. We paid to decorate their living room, which was the other side of the house.

Bumpa?

A 4" grinder and a steady hand. Mark the square neatly and overlap the lines a bit. Cut one side up to the corners, then turn the tile over to complete the cuts.

You can get attic trusses with EasyJoist bottom chords so you can run services through them. You cannot otherwise drill any part of them without written agreement from the designer.

Agreed with @Temp. The simple exchange of letters will save you at least £1,000 in fees.

If the ground is nice and solid it is an ideal way to do it, as long as you don't want to build any heavy partitions. For some reason on a new build they will insist on a concrete slab. It is not needed.

He is using Hi Therm lintels.

What is the budget? Insulation and airtightness/controlled ventilation will be key to better energy efficiency. Would you look at external wall insulation?

+1 another vote for medium weight aggregate blocks 7N

The £40 in N. Ireland could easily be £100+ in SE England. Resin works well as used by @Bitpipe and

Also bear in mind that when these fail the tank full of sewage is not all that bad. Maybe I have poor sense of smell but lots of it will be water from showers, dishwasher, laundry. Obvs a fair mix of floaters but the contents are regularly pumped away.

I have installed a pump station in the past. Although you can go for very expensive pumps, 2 pump systems, rail mount etc I think it is sometimes more practical to just have a fairly inexpensive single pump with chain plus a spare stored in the house. Don't bother with servicing. If the pump fails, swap it out.

I guess if your bathroom does not have a window, turning off the MVHR would be a bad plan.

A friend does these. He likes FAAC for the openers and Videx for the intercom. I have a Videx intercom on the front door and have had them fitted elsewhere, including gates. No issues.

No. When you commence development, the planning consent is locked in. PD rights come into play when the scheme is complete.

You don't have PD rights until the building is completed so if you carried the work out before it would not be PD. The LA may ask you to apply for a Certificate of Lawfulness or full planning consent, although they would probably not know unless a neighbour objected. There are different types of PD, so involving neighbour consultations and it is these that could be an issue. If you sell the property and have not got full consent on what has been built, the other side may kick up a fuss. If you have knowingly sold without planning consent and told the other side you have fully complied, you may be in breach of contract.

Those slabs look like an osteopath's dream! I always go with advice from https://www.pavingexpert.com/

The difficulty with a specialist product is having a reliable local supplier. This looks like a natural slate in special sizes and it could be a real pain if you run short of the odd clip or trim and find it takes 3 months and you need to order a pallet load.

I have done a basement in ICF. We used Polarwall. You need to make sure your warranty company is OK with it. You must use type C internal drained cavity membrane and pump, as it is not possible to guarantee that the concrete is contiguous in the forms. The reinforcing and concrete thicknesses is the same as if you did normal shuttered RC walls. We used Easi Joist floor above and this was treated as "partially propped" for the structural calcs. We did timber frame above. The basement was the same footprint as the floors above plus a light well.

Hi Helen I am also in Sussex. Have you got planning consent for a design you are happy with? Scandia Hus do fairly standard timber frame and can be quite expensive but worth keeping on the list for comparisons.