has anybody any ideas apart from all the normal solutions about bad walkers on the lead, fine off the lead very obedient but as soon as a lead goes on his neck goes beserk, will chase cars anything near enough pulls your arm out of its sockets, have tried ordinary lead, halti etc just at a loose end now, by the way the breed is border collie, not my first i have 5 no problems with the others just this young man of 4 years