Amazing - thanks for all your replies!
We'd keep a downstairs loo but move to under the stairs. The kitchen looks bigger than it is in that photo - it's currently too small for a family of plus au pair plus dog. We want to avoid going into the side return if we can help it (for money and losing garden space purposes) so hope that knocking through to the end will give us the space we want/need.
The whole thing looks lovely in the photos I know, almost like it has been recently decorated in a vintage/retro style, but up close it's actually not been touched since about 1972 and everything is peeling, a bit brown etc, so it does need taking back to its roots and re-doing.
Survey came back saying there is a little bit of damp but nothing major and should be covered by the current owners damp guarantee (we are investigating through solicitors).
I realise the garden in tiny, but it was a lot better than most of the others we looked at in the area! London gardens are just so hard to get without compromising on other areas of the house/location. I know 1.15m could buy you acres and a manor house in other parts of the country but we can't work there (and the kids' school is London based as well, so the commute wouldn't work)
Yes I know it's a how long is a piece of string question - I just like hearing people's ideas and approx costs for what they have done. I would say we have middling taste values/costs - not Ikea but not a 40k bespoke kitchen either.
I think we will have about 50k in our total budget and just wanted to see whether I was dreaming to do all of the above within that amount but obviously without knowing things like load-bearing walls etc., it is all finger in the air stuff.
Appreciate the replies though, thanks.