Thanks for the advice. Actually, I did mean to say that one of the reasons why we probably have rats, is because we feed our badgers and foxes of a night-time which we don't really want to stop doing as we love watching all the wildlife that we get in our garden and I think they need all the help they can get, especially since there'll be little ones soon!
I really hope it's bats in the loft too, and we most definitely would let them stay if that were the case. Hopefully we will be able to sort the problem out ourselves, but if not, then I suppose we may have to contact the Council. Fingers crossed it's bats!
Re moggies in garden - we do get a few in our garden actually but they're obviously not doing their job!!