I agree one class can't give a long term sentence.
I also e-mailed Carrie she is an animal behaviorist in the UK . She was a reg. her before she got so busy , I hope she can give you some help.
I think puppies are rough players couse they are learning social skills. I have never had this in a puppy I just had chows that I rescued that had not been socialized I never could feel safely take them out in public. They were 3 and 5 years old when I got them . Did get so I could trust them with my 9 and 11 year old kids. I would get Budda around lots of other animals and be encourageing on proper play and stern on in proper play. Like sitting out a few mintues and allow oly watching of play. Time out type of thing. He has to learn to be tolerant of others. He may not like certain dogs. Merlin even does that some are just like people some you just don't like. He's a springer and thinks most dogs were put here for him to play with. Good luck and I do hope carrie can help you.