looking at the building on Google maps, I presume it's the right hand flat over the pizza shop?
Looks like the roof is sagging/dropping away from the party wall. The lintels over the bedroom windows look to have twisted. The guttering needs replacing - it's twisted. And the brickwork looks a mess (see what a state it's in next door where the windows have been taken out and boarded - soft and crumbling.
All look like little things, but it all adds up to a fucked building that needs a fair bit of work. Key question is how bad are the roof timbers? Could just need the tiles (especially that lifted ridge tile) reseating. Could need something more drastic