Pets

The best way to stop him pulling is to take him to Dog Training Classes but meanwhile any decent harness should help.
Is he anxious when he’s left at home or around other dogs?

A really effective one is the Gencon lead. I agree re the puppy training, however mine went, passed and got the certificate from the Kennel Club as well, but he still forgets and pulls.. he’s a cocker spaniel, and they are notorious pullers. I keep checking him, but when he has the Gencon on he doesn’t even try.

I've never had a dog, but I heard a neighbour thanking another for telling her how to stop her dog pulling. I think it involved gently wrapping the lead around the dog's muzzle so that it was controlled by its head, not its neck, a more efficient method. Presumably the sort of head collar with lead that you can buy would be better and more comfortable.

Your dog needs more than a harness Benji8 , he needs proper training. Training that should have started long before he reached the age of 13 months. Has he been properly socialised? What sort of anxiety does he have ?

It would be a valuable start for you to get a professional dog trainer or behaviourist to evaluate him so you know what you're dealing with. Even local dog training classes would be a help.

You can buy any old harness to be fair but unless you use it effectively coupled with decent training it wont be much help.