The rules may have changed but when we built our extension the wall adjoining our neighbour had to be completely within our own boundary. It looks as if your neighbour has continued along the party wall and therefore half the depth of the wall is on your land. It might be worth getting a chartered building surveyor to check it out as otherwise it may cause difficulties when either you or your neighbour come to sell. If I'm wrong about this maybe a professional on here could correct me. Other than that I think you should make the best of the little private courtyard it has afforded you by using plants in pots and climbers to soften the wall.

If you take the wall down between the hall and front room you wont get any more furniture into it as it will still be a corridor. I say save your money here. Personally I would put a dining table in here. The back room with the stairs will make a lovely living room. I presume the upstairs is not big enough to put the bathroom up there. In the kitchen area I would put the bathroom in the sink area and then put the kitchen at the garden end so that you end up with a lighter kitchen and a bathroom with no window. Plus this way even though your kitchen will be small now you may be able to extend it later.

Hi amfork, I went ahead & put the hob on my island & am delighted I did. I find it really is so much nicer looking out at the kids/my husband & being able to chat to them while I prepare meals as opposed to facing the wall with my back turned on everyone. I put a 4 ring induction hob on the island & put a 5 ring gas hob on counter facing wall. I did this as I have a large extended family & we frequently have get togethers. It’s great for catering for big events. However, I use the 4 ring induction hob on a daily basis. Hope this helps! Best of luck with your project, Claire

If you don't want to make the wall itself straight, maybe consider playing with some deep shelves ABOVE the TV, that could go from the diagonal wall to the straight line where you want to put the TV. Then behind the TV you could have a vertical panel of the same colour/material of the shelves (or matching the colour of the wall) to connect the TV stand to the first shelf and hide the awkward wall. To avoid having empty space right beside the door you could put a narrow shelving unit (with a back panel, not an open one) between the TV stand/panel and the straight wall (or beside it if it's short) that goes from floor to first shelf, again I'm imagining same colour/material of the rest so it binds seamlessly rather than looking like patchwork to fill the space. It's a little complicated to explain but I hope it makes sense!