The first real, “we have heard it together” noises of a “there’s something else alive round here apart from us” type rustling heard in the pile of carrier bags under the stairs. Put gloves on. Shall I do it, or will you – okay I have the gloves. There’s a lesson to be learnt here, but too late. Nervously remove everything a bit at a time – don’t want to get bitten or anything.
Ultimately reach floor, but nothing live to be found. However, Tesco bag which was hanging up (made of that material like enviromesh/fleece you put over delicate plants) has great toothy rips on the side where access has been gained to the chocolate bars hidden inside (hidden obviously to children, but apparently not to rodents). Judging by the evidence this has been a favoured source of food for some time. Throw out quite a bit (teeth marks are less than appealing), clear the area up, and resolve to keep clear in future. Clear proof that another exit from under the floorboards has been created.