We've just bought a house of a similar age, similar size and sadly similar decor (!) though the layout is slightly different.
If it's any help this is our rough project budget:
Kitchen/Diner/Family Room
We're taking a wall down between the kitchen and dining room which is a structural wall and one between the dining and a small living room which isn't. Similar to us the wall you'd need to take down is a supporting wall by the look of it (similar wall above) so you'd need to factor in a structural engineer (we've paid nearly £1k) and building regs which I think are in the region of £260 though we're doing it privately as the council ones in our area are realllllly slow.
The changes we want to make including fitting and painting the kitchen, plastering, flooring, adding the steel, moving a radiator and some additional plumbing is costing us nearly £20k for the building element then £7k for units (Handmade Kitchens of Christchurch), 3k for worktops and £2k and a bit for appliances (we shopped around on the internet).
Have you thought of maybe moving the kitchen into the existing living dining room and keeping the kitchen as a separate study? Costs would depend on where your pipework is but you'd save a lot in structural engineer costs and steel beams, still have open plan but also have the separate room at the back.
Because we're touching the kitchen wiring we need a new fuse board (consumer unit) so the electrics are costing about another £1.5k plus parts so new light fixtures.
Main living room and bedrooms::
Remove coving and reskimming the artex ceilings are between £300-£500 per room depending on the size.
Then about £1000 for decorating each room including paint
Bathrooms:
Main bathroom is going to cost £3k to refit and tile plus costs for tiles and bath, shower etc.
Ensuite is smaller so around £2k plus fittings
Downstairs loo is about £1k plus fittings.
Flooring:
Downstairs flooring is £1800 and fitting costs are included in our kitchen budget. We got a very good deal on some really nice laminate from local flooring people we have used before.
New carpets for upstairs are going to be in the region of £3k including fitting and underlay
Windows and Doors and Rendering:
There is a big chunk needed for the windows and two sets of rear doors at nearly £20k but it's a 1970s style house built in the 1990s so they're big but still the original ones and they're in a bad state.
It will be about another £7k to render the outside. Fortuantely we don't need to do anything to the roof!
Fortunately my husband is the finance person because even writing this down is making me feel a bit sick!