Mice

Hi all the other night I was out slug hunting with my torch when I heard a rustling from my top border and shining the torch I spotted what I thought was a dormouse running along the top of some large stones I had placed at the back of border to hide the concrete boards at the bottom of the fence. Have submitted a description to wildlife trust as they are supposed to be extinct in Derbyshire has anybody else got them not seen them since I moved in last May they might be sharing bedding with my rabbits and guinea pigs who have access to the lawn/garden via a tunnel from the garage. Saying that no sign in the garage of mice so hoping it is dormouse rather than house mice etc.