I done the exact same thing over here with my old dog on two properties, I got a friend to take him for a walk anytime the landlord came over and then the other I just didn't say anything until the landlord came round unexpectedly and saw a great big Akita in the garden! I came clean and said it's mine and offered to pay a bigger deposit but despite admitting not liking dogs, she said no let's see how it goes...kind of lucky I guess.
We have two dogs at the moment and have come to a decision to leave the older one here with a friend as she's ten now and don't think she would cope too well with it all. We are in a bit of a dilemma with the younger one, as much as we love her, another friend has offered to adopt her and we know she would have a great home. Obviously would make finding somewhere to live a lot easier, but making up our minds to bring her is proving difficult! Thanks for the advice