There are always needs to for rooms, so do not worry about what kind of rooms you have
. Let it be a small house in the countryside or small single room, there might be someone out there looking just for that. Post a note in the bulletin board or pay to have a listing in the newspaper. If both ways failed to get you a tenant, then you can go through estate agencies and they will help look for a tenant for your flatshare in London but for a price.