Sonic Mouse Repelent Kit?

It is that time of year and we have our normal fury visitor arriving to munch through our bags of semolina and wheat germ for bread making (how blinkin' middle class does that sound...). Anyway, apart from the inevitable holes in bags of stuff that then needs to be chucked it craps etc everywhere, so we are less enamoured with our visitor than we could be.

Given a cat is no on the agenda, does anyone have any experience with sonic mice repellers at all, indeed, does anyone have one in the back of a cupboard they are not using or do not need? The clever little sod is not going for the traps.

I came down this morning and chased the little sod round the kitchen as it was happily munching in the cupboard I went into. Nice!