We have a wonderful 3yo rescue who has been with us nearly 2 years. We also have a fantastic 9yo golden retriever who walks off lead, but I am too nervous to let the rescue off lead, as she has a strong prey drive and although her recall works fine with no distractions (like in a dog walking field) I am not sure I trust her like I do my golden retriever, who will disappear regularly on walks but always comes back and rejoins me. I'd be keen to hear of any tips. Or should I use a trainer?