Mr Punter

If all the extensions to date have been authorised or carried out as full planning applications and were approved without a condition withdrawing permitted development rights you may be able to do the enlargements required under these. If the house is a real dog's breakfast and the location warrants it, you would get VAT back if you demolish and rebuild, perhaps with a couple of modest sized dwellings taking up a reduced footprint compared to the existing (once extended to full PD).

You can borrow 4 x wife's earnings, so £80k, as long as you have no other mortgages.

It is quite unusual to have a timber ground floor where you are. I assume you are using rigid insulation by the thickness. On a roof or wall the breather membrane is there to keep the rain out and let the structure breathe. With a floor, the rain is not an issue so it may be OK not to have a membrane. You will need plenty of ventilation under the floor to take away any moisture that may condense in the timber, especially where it meets the substructure. 150mm is quite skinny for floor joist but I guess there are sleeper walls or intermediate supports. For VCL above you can use normal DPM (and tape the overlaps if you really want to).

Another vote for Guttercrest. I once had some aluminium gutter powder coated to RAL 9007. It was really pricey and once installed looked almost identical to plastic stuff which would have cost less than half, so perhaps don't rule out plastic.

On the recommendation of others here I have used a couple of Ubiquity Unify AC lites and I now have seamless WIFI throughout a 4 storey house.

Not an expert but would it be acceptable for you to just raise the ceiling, so the new ceiling joists could still tie the rafters together?

Yes I think it makes sense to get legal advice. Just make sure you don't spend a fortune on something that has no value or potentially getting involved in an expensive dispute. I do not think the mortgage company will be interested in there being someone's pipe under the track.

I imagine they are not keen on racking up legal fees - which could be £££ for something where they consider they already have a right. What did the solicitor who did your purchase conveyancing say?

I have never dealt with a share of freehold property. What leverage do the other freeholders have to oblige this to be advertised as 1 bedroom in sales particulars?

These issues can cost lots of money to resolve. Without the title plan and deeds it is not possible to give an answer. Why would the value of your land be reduced by having a water pipe under the track?

Not me rendering! Either a bell cast of the same depth as render or a stop bead.

Not very good ones but the top one is render onto cement board, the bottom one to blockwork. I just don't like the massively flared look with some bellcast beads.

1050 to 1100 works well. Building Control are not interested.

I have seen quite a lot of through colour render look grubby with unsightly dark grey and algae patches and K-Rend is no exception. I prefer a cement based render finished with masonry paint. I have used Weber OCR on blockwork and Weber LAC on cement boards. Probably others are just as good. I prefer the bagged products for quality and consistent mix although they cost a fair bit more than rendering sand / cement / lime mixed on site so if you have a lot to do this could be the way to go.

Agree with @ProDave wrt the stoves. This also means no flue pipe in the master bed. Perhaps move the door to the lounge in the annex down the corridor a bit. Make all the upstairs bedrooms ensuite. Make the ground floor fully wheelchair accessible including bathrooms. Consider shower rooms where seats and grabs could be added. The main utility is large. Consider a WC in there.

Hard work doing that. Did you knock up the plaster as well?

It is normally acceptable to have bare earth as long as it is weed free.

Yes @MJNewton screws horizontal or even better with cover caps.

The wrench will only work on a hex nut of bolt. The pliers will grip most things. What do you need to grip?

@Amateur bob will not build a 270m2 house for £200k. 150m2 may be doable.

It is quite poor. Nobody has done a decent job and it has not been managed properly. Not sure of the tanking design and junction detailing if this is supposed to be a wetroom. If they can't say I would take the tiling off. When I have tiling done the tiler is responsible to clean grout and polish tiles. I don't know how the floor drain works or if there is something else to go over it? I imagine the stub of waste pipe is behind the sink? I would want flooring replaced but please do it after the ceiling is plastered and painted and the extract hole done. Bodgetastic but it really did not need to be.

If they lend 4 x joint, then you would only need to earn £5k together with your wife's £25k. They may do additional affordability tests. Presumably you have no other mortgage? £200k is very tight for a 4 bed house, so make sure it is very small and simple.

Mortgage lenders will want to make sure you have an income that is enough to comfortably pay the interest, plus the capital amount over the mortgage period. For self build they will want to know you will have sufficient funding to complete the project as they will not want to renegotiate part way through. A multiple of salary is normally a quick and simple way for them to assess how much you can afford. I think you would struggle to borrow more than 4x provable joint income. The days of self cert mortgages are long gone.

Just to clarify, you will not be able to just do a Prior Approval permitted development application because the building was not B1(a) on 30 May 2013, so you need to do a full planning application.

I would go for a 926 door if you have room. I would make the opening 1000. If you have check reveals on 2 skin make the outer leaf 980.