Hi there!
I live in a fairly small maisonette and still planned a home birth for my first who is 3 months now.. (I ended up being transferred in to hospital, but I was still really glad I started out t home). I would definitely recommend it.
Firstly I would say that it is too early to be worrying very much. I know that you probably want to get things sorted out in your head, but you won't need to make a decision for a while. I would tell your mws that you are considering it though, I think it's easier to change from a home to hospital rather than the other way if you change your mind at the last minute or your circumstances change.
As for being in a small flat, I'm sure youcould make that work, but it will just take a bit of planning! For instance- if the bedroom is a bit hard to get to, could you use the living room for the birth? We had a birth pool in our living room, or you could get a cheap mattress for the floor. Then you could get to the bathroom more easily!
When I requested a home birth my mw came out to visit us, mainly to see whether they could get easy access in an emergency, but we also asked them about the setup. Once you know where you will be, the local mws might do something similar.
HTH- sorry if it is a bit long!