Update on the mouse problem:
Dogs have been away to my parents and I have not caught a single mouse despite having 12 traps down for over a week. I also can't hear them nor have any signs.
What is strange is that, before the dogs left, there was obvious signs of a mouse in a cupboard. I haven't caught this mouse in a trap - but Pip was here for a day and a night after seeing the signs. I can only assume that the lonely mouse has left or Pip has also eaten that mouse (and god knows how many others!). He was taking his duties as mouse catcher very seriously and was patrolling the kitchen (i.e. wrecking it) to get them. Whatever, Pip seems to have solved the mouse problem.
Who needs a cat when you have a mouser cocker!