Hello again to all on here,
My rehomed pom-mix  5 month old puppy has settled down at night now, and is doing quite well in his house training etc, but I'm at my wit's end about this new problem. I take him to the local park most mornings and he goes to puppy classes every week so I'm really trying to scocialise him. A few weeks ago a dog who lives on my close went for my pup and he pooed himself in fright but was not physically hurt. About a week after this,  my pup started barking at anything that moves. He does it especially at dogs that resemble the attack dog, but at any dog really. In the park he barks at a distance, but once the approaching dog gets to him, he stops and plays really nicely with the dog. No aggression to any of them. I have tried rewarding Quiet, and ignoring it, and turning and walking away from the approaching dog, but he seems to be getting worse.  Sometimes I can distract him with Quiet and a treat, and he stops and just looks at the dog, but am worried I'm indirectly rewarding the bark...He also barks at the doggy chums he has got to know around our park until they are actually upon him, then he plays with them tail wagging. I'm getting very confused what to do, and find walks very stressful now. Someone said it's just puppy behaviour and to ignore it, but others think he has a problem. Could this be because of the attack, or am I missing something else?  Any help would be very much appreciated.

it's because of the attack....

your pup is clearly nervous, so needs to be out and about more (but not put under pressure to be nice) with friendly dogs to help get over this - you need a lot of positiveness, not encouraging the nervousness and praising when your pup is brave... as you say ignoring the behaviour you don't want.

I'd cut out the park and meeting unknown dogs approaching which clearly frightens, but try and get a group of friendly dogs to play so that your pup gets over his fears in a controlled environment, slowly working up to going out and having strange dogs approach...