Oh I love a bit of house hunting.
Not the East Finchley one. That second bedroom is shit and you are really far out. It is like £100k cheaper than the other two, you can do better if you have £600k to spend.
Can't see anything other than the floor plan for the N1 one, but the floor plan looks really good. 800sq foot is decent, and a spare toilet. Lovely location if you will bike or walk everywhere.
The camden NW1 one is also a good layout (but you would have a sep kitchen, diner and sitting room plus 2 equal beds and 1 bath) but that road is hell busy. I'd want to be facing away from it.
I would need to go and see the blocks, that will make all the difference. As will location in the block. Some blocks are well maintained and some are really crap. I viewed on ex-LA flat with drug dealing going on outside the front door!!! Not snobby, I bought ex-LA before people jump on me. But I didn't buy that one ;-)