Last night the mouse returned :( so today I've bought two different types of traps. One is a pre-baited box they are supposed to die inside - I've put this one down on the kitchen floor. The other is a traditional snap shut trap for backup if the other doesn't work. I was showing the snap shut one to my sister and she was trying it out with a bit of stick - she was quite shocked when the stick was broken by the force of the trap shutting.
Back home I removed the bottom piece of the fitted cupboards and cleaned as much as I could get at - hopefully that alone should discurage the mouse.
Right, off to pack all mouse edible stuff into some plastic boxes I found in the garage.