WELL.
I have had the pleasure of doing a self build. Even if I did not do the carpentry myself , nor the brick laying, the planning and the budgeting was nearly a full time job. Decisions, decisions, decisions. Which kitchen? Bathroom? What is the optimum layout? Knobs? doorhandles? Flooring had me floored, I tell you that. Could not afford wood flooring everywhere, had to go with laminate in some rooms. Have you any idea what flooring even cost?
I have also the pleasure of owning a house in London, we have to redecorate the entire house. It is not a big house, it is a three bed end of terrace. 4k was the best quote from the decorator only for painting (including paint). We have quotes for 1k for all the upstairs bedroom carpets, this is the cheapest carpet you can find in Allied Carpets! Some damp was found, and part of the plaster had to be ripped out, and new plaster, and new damp proofing under the doorstep, specialist jobs we cannot do, or ask a labourer to do, is nearly £3k. This is the house we lived in comfortably for over 10 years, with no idea there was any issue with missing damp proof course under the doorstep.
Have you had a structural survey done?
Until you sit down and work out what decorating is going to cost, what a kitchen will cost, redoing the bathroom, and new flooring, you dont really know. Even if this is cosmetic, and not "major" work, it will still cost a packet.
We paid £10k for our lovely new kitchen in the new build, and £8k for two bathrooms. The bathrooms had lovely tiles, but we opted for cheap-ish units, to stay in budget. I had my heart on a walnut worktop to go with the high gloss white units, but ended up with a grey industrial laminate, which is also cool, but does not have the OOMPH. The kitchen is lovely though, it has to be as our living room and kitchen is open plan. There is a lot to plan, and work out, and budgeting is possibly the most important part. You cannot go over budget, you must at any time know what the work is going to cost in labour and materials.
Our small London bathroom cost £5k ten years ago! Tiles, shower cubicle, stylish sink and mirror, and a modern slim fit toilet bowl.
If all is going to come out of your salaries, it might take a while!
I would measure up, take the plans down to somewhere like Allied Carpets, ask their opinion on what it is going to cost for new carpets, new laminate. Speak to a decorator about how much paint you will need, etc.
Get quotes in for kitchens.
Because you dont want to live in a house that had the potential to be lovely, but because you neither had the time nor the energy, nor the money to get it done well, you are living in a mediocre dump which had potential.
I had a massive spreadsheet, with costings for everything. I had my budget highlighted on top, and for ever item I added that went beyond the budget, something else had to come out.