I hear you OP. I'm about a year ahead of you and have seen prices blown out of proportion in just that time. We bought an un-livable, derelict property which had been empty 7yrs. Originally built about 1920's, but not touched or updated for 40yrs+.
I'm glad you found out about the 5% VAT to get it back to a livable state. Most trades are aware of the new build scheme- but very few are aware of the derelict home scheme. Even after seeing our council certificate, many companies and trades have said they won't accept it, WE need to claim the VAT (not true!) or ignore it! We have, however, found a few companies (a building suppliers merchant, electrics and plumbing company) who accept it. With most trades, we have therefore bought the materials and just pay a day rate for trades.
Do you NEED an architect? If you know the layout and plans you want, just get a draughtsman to draw them up. For a qualified architect, we were quoted between 10-20% of the overall build. I might be naive of the costing, but I don't understand why they should get paid more- if I chose a gold plated bathroom set or a swarovski door handle? Surely- they should be paid to draw up the plans- not dictate a price based on what overall cost it is?
We have been living in a tiny static van in the garden. Would this be an option? or living in a garage? We have some boxes and stored items in the house, but despite rooms being sealed off etc, the dust and debris is awful. I would NEVER try living in a house undergoing the amount of renovations our houses need. Where are you living now?
We aren't in central london now, so different I know, but we have tried to use local trades, recommended by other good ones. Our roofer recommended a builder, who in turn recommended a renderer etc. We did get other quotes for everything though. We have been very fortunate, but equally, we are aware that this house is like a piece of string. Things will be uncovered that no survey would have found. Once walls are removed- hidden problems can be visible and in our case- they have.
We took out walls to open up the kitchen diner. We were given a quote for steels- which they could only guarantee for 7days- otherwise the price went up again. Most other quotes were for at least 28days, so we are living in crazy times.
DH and I both work full time- but have no children. DH in particular has had to learn a massive amount about various renovation tasks and we are essentially project managing it. Will you be managing it yourselves, or paying someone else?
Ours if a 4 bed, 2 storey in Sth East. Everything had to be stripped back, re wired, new plumbing, insulation, new roof and tiles, all new double glazed windows (over 40 of them!), 3x4m extension, 3 chimneys removed, walls removed and 3 massive steels put in, dug up existing concrete floors and lay again (building control said it wasn't thick enough!), 100 tonne of rubble removed from garden and house, underfloor heating put in then a screed on top. Lots more has been done but so far, we are at £200,000. 1st fix is pretty much complete. This doesn't include the cost of the kitchen, 3 bathrooms, flooring, appliances or decor. Let alone actual furniture! We expected to spend about £100,000 when we started. We did expect to find extras to be done, because you just can't predict exactly with a derelict property. We didn't, however, predict the affect of brexit/covid etc when we started. We plan to live here for many years to come though and to have a massive garden, friendly street in a lovely area has been worth it so far.
Sorry this is such an essay! If you have any questions please ask.