John,
He's looking very nice! Time for a higher fence, your tempting fate. If I leave the older Britt alone by himself he'll be running channels looking for ducks until he's tired ... usually about an hour of solid swimming chasing the ducks does it for him. Something flapping in the distance would have him over that fence, though jumping into an electric when he was younger has tempered his greatest urges to jump fences.

Just some thoughts ... maybe back to recall basics on a check cord to get him through the "I've got it in my mouth, I might just dawdle and have some fun Dad' otherwise backpedal and watch him come in like a rocket! If he doesn't want to hand over, possibly teach him to come back, walk around and sit beside you as if at heel ... then take it off him once he's relaxed a little.

Who cares though, he's just an unruly teenager.
Cheers...
Con