Well, I tried running with a 17 week old Lab x Collie last night, with my wife cycling along too. It was rather interesting, and not necessarily to be recommended.
I seemed to spend as much time emptying her mouth of horse poo (the dog, not my wife) and stopping whilst she sniffed at some unseen smell in the verge (again, the dog). I think I shall stick to solo running, or running with other humans for the time being. This way I shall get out for my run as well as as taking the dog for her evening walk. A real win-win for me, especially if I can get a ride in too!