I have set traps under the floor again as activity has picked up.... loud squeaking, saw what I thought was a mouse scurry behind the fridge but in hindsight think it was probo a baby rat, they have tried to break into the cupboard in the lounge via a broken floorboard.
Have caught 3 in the traps over the last 10 days but only babies.
As I sit here now at the dining table I can hear one building a bloody nest with a carrier bag that's under the boards. 
I put poison down but I can't get it down there quick enough - it's quite expensive and as long as I keep putting it down there, they keep eating it, then crawl into the walls and other places I can't get them to die. They stink to high heaven. Like roadkill in the summer mixed with dirty nappies.
Live in a terraced run so think I am probably feeding hundreds with the poison.
Worried about them chewing stuff they shouldn't and having a fire more than anything else. :(