Aww that's a lovely story Taz!
I've just done the shed inspection with my torch and I
think I saw a couple of droppings (hard to tell cos the floor's a bit mucky) but no sign of mousey. I've suggested to himself that we clear out the shed at the weekend and fix the door. I think perhaps mousey was just sheltering in there while it's been so cold. I'll know more when we've cleared the floor on Saturday.
I did a bit of research on the net and it definitely wasn't a rat, it's ears were too big and it's tail too long.
Mice can be sooo cute can't they?

If I find him I'm going to give him a name.
Maybe I could feed him on the quiet

Catweazle x