In the print shop at Amberley Museum where I volunteer, we have a regular 'mouse run'. He (or she) will come out at any time of the day, however busy we might be, and take the usual course across the printshop floor and out a side door into the rough area of ground - sometimes he takes another route where the visitors are, which creates quite a stir if someone spots him, but we just say 'Oh!, there he goes'. In the winter time, when the print shop is very quiet, we can hear them rustling in the walls.
About the shooting Jeni, a long time ago we had someone shooting locally, we could hear it, and reported this to the police who looked into the matter, and it was stopped. We were concerned about a riquochet, which is something you might consider.