Ok, you are in what is commonly known as "The Freak Out Stage" - overwhelmed by all your options now that the time has come to actually do something! I scrolled through your Ideabooks and you are right - you sure have lots of things you like - but generally there is a theme: with a few exceptions, they are cottage-y and traditional, lots of fabrics, and neutral walls in beige/linen/light grey. Often you've picked out photos that are overall neutral and calming, with one brighter piece (a chair or a nice fabric in cushions or a throw or curtains). I say all of that to give you confidence that there is a cohesive look that you like so don't freak out. If you need to do essential works, like the windows, do those first. Restore the cornicing (even if some sections need replacing, this isn't a major job - the pattern is just copied into a mould and inserted and then you paint) and then decide if there is a room you can complete that won't get damaged or need re-doing further down the line when you are working on other rooms. Depending on the layout and your plans it could be your lounge, kitchen or bedroom. When you have one room done to your liking it won't seem so overwhelming. I hope this is somewhat helpful. If you want specific advice for particular rooms, post some pictures and I'm sure there will be loads of people on here who can help guide you. Good luck!

I've just cobbled together a quick plan for you and then on re-reading OnePlan's suggestion above I realise its the same thing so apologies for that. Wasnt trying to copy. If you have more accurate dimensions I'll happily put together something a bit more accurate. With this plan you lose a bit of space from the front room and the bedroom but you turn the flat into a 2 bed, great for when you come to resell. To get light into the bedroom you could have a frosted glass panel in place of the existing window and as long as there are rooflights above the kitchen then the bedroom will get some light but its not going to be a great sunny room.

Update: I did a bit of DIY and hacked a wine box I got from Odd Bins (most of these big chains sell the wooden wine boxes for a donation to charity). I really liked the console idea, but needed to incorporate storage (this is my new knitting box side table!) So I adapted it a bit. What do you think, chaps? :)

Have you thought about painting the wall behind that beautiful bed a different colour (maybe the soft pink suggested previously)? At the moment the bed disappears a bit against the walls, which seems a shame. I think pink could work rather well with the dark grey carpet, too.