Hi I did a similar job in my own home so hope I can be some help. I think you might be a bit tight on 20K to do it all but suppose it comes down to the finish you want. A bit of advice Id give you is dont scrimp on things like kitchens & bathrooms, as in get something you want and can live with rather than do it cheaply. I still have the same suite I had when we moved in 4 years ago and dying to change it but have spent the money in other areas first
Firstly is wall being removed load/non-load bearing as theres a large differance in cost once you factor in engineer, support beam & cert of compliance for a load bearing wall. So heres the breakdown of what we did
1) Remove load bearing wall & fit RSJ
2) Move Rad from above wall to another wall
3) Completely replace kitchen (as kitchen was moving from one wall to another this involved moving mains gas & elecs plumbing and sockets so bear that in mind)
4) Remove ceiling over kitchen and replace to follow pitch of roof and fit velux windows
5) Replace all downstairs doors/frames & architraves skirting
6) Fit wooden floors sitting room/hall
7) Replace bannisters with solid oak ones
8) change all sockets/light switches to chrome
9) Wire and fit under unit lighting and spotlights in kitchen
10) Level floor ready for tiling
The builder we used supplied everything above (we'd just pick out) except the doors which we paid for and granite worktop which he organised and we paid supplier. And final figure to builder was e23,700. That didnt include tiles/tiler or appliances which also came to a few thousand so we figure with paint and other bits and bobs we spent ~e30,000. While we could have done it cheaper we did it the way we wanted and didnt cut corners. Remember itgs your home and you have to live there