Block holes with wire wool. They don't like it one bit. A rat can squeeze itself through a gap about the size of a twenty pence piece. This means they use pipework and the shoddy workmanship plumbers throw systems in with to their advantage, up and down the walls, in the recess, and appearing under the bath or the sink, or the airing cupboard.
Get a tall bin for your kitchen, one they can't jump up into (rats are accomplished jumpers) and always put all your kitchen waste away asap. Might be worth checking your cupboard spaces, if they can get under the facias they might have an entrance to somewhere you store cereal or dried goods like pasta or pulses.
This stuff works, but you can only use it inside your house, you are not allowed by law to expose wildlife outside your home to it, it is and will be prosecutable to do so.
I hate rats. The ones I caught don't like me.