Hunting around for more evidence I found what I was looking for when I opened a wicker hamper: shredded paper - lots of it. The mice had decided to set up home there and even Monkeychild's old baby-food jars that I was keeping for some jam making, were filled with a layered combination of rice grains and paper. Very snug. The little blighters had made a hole in a large bag of rice that we had on the floor (luckily we hadn't used it ourselves yet) and had smuggled the grains into their abode.
Everything was turned out of the pantry; foodstuffs binned which looked 'moused', shelves, walls and floor cleaned with sterilising solution, crockery put into the dishwasher at the highest temperature and everything else cleaned with anti-bacterial cleaner.
And I've only just finished!
Here's my ultra clean pantry, ready for Husband to fit draught excluders to the bottom of the door where the mice have been getting in and position some Little Nippers for any nocturnal intruders.
So much for my afternoon of knitting and lounging about. Now how does that saying go...the best laid plans....?