Revisiting the bait sites I discover the trays in the kitchen are untouched, which is good news, but the one I put under the sink cabinet in the bathroom had disappeared! I have an image of a family of mice living in a red tray marked 'Poison' somewhere down there...
Perhaps we need a couple of new games, as we've not had any in 8 months (ignoring Mystery Crescent, restarted after running out of steam. Well gosh, it's run out of steam again!)