so, in saying that.. DH came home today with one of those traps that just traps heaps of live mice, he said screw it, we will deal with them when we have to and he would rather have the live mice running around in it than around the house. We are also doing a bit of reno to the house (mainly turning a normal door into a slidding door) and he got some of that filler putty stuff for the door, and i've filled a few small (like 1cm) holes around the place that I'm sure mice like... but they are in the walls and the roof, so can't really putty them out for good.