Agree with Barry, - only way is to start training the basics again and try to aim at making what you offer as a reward for coming back, more exciting than whatever is drawing Tramp‘s attention. For food orientated dogs, high value treats for a good quick recall (- i.e. IMMEDIATELY, a bit of“ considering if its worth coming back“ before finally coming doesn’t count!
) :can be effective (but only as a reward, not as a bribe!), other‘s will drop everything for a game or a ball. You could also try a whistle and then use a really favourite high value treat that he only gets for a perfect recall and at no other time. [ I fry up some chicken pieces and freeze them and then just take out a couple of pieces as I need them but cubes of cheese or sausage are also super treats for Humphrey)Try and deliberately up distractions, maybe you can enlist the help of someone else with a friendly dog so that you can practice that specifically and in as many situations as possible. Oh, and practise, practise, practise, - its a continuous training unfortunately, they conveniently forget things very quickly as soon as you let your eye off the ball!