A few facts about training a dog to work off the lead. It takes time, and there will be accidents along the way. Over the years I have found it better to ignore the accidents and concentrate on the positives. I would not try and presume to try and tell you how to train your dogs, other than to say dogs pick up things quicker than you think.
If you have never worked a dog off a slip before, you would not believe how much more pleasurable it is, no faffing around at gates or fences, both hands free, plus the added bonus that the dogs get to learn that when they are on the lead everything is