After an 'incident' withthe harness and bike lead, I realised his recall might not be so terrible. He came back straight away, first time, despite distractions.
My Dad thinks I should take him down the doggy part of the beach and let him run, because it's all beach and sand dunes for miles, so if he doesn't come back we can just sit and wait him out, there are no roads he could run onto, plus the theory is he will follow Whippy and the others back when they recall. And he loves my Dad so he might come back when he calls him.
Or did he jsut come back because he loves running with the bike more than he loves chasing other dogs and letting him off would be a disaster? (this is my theory)