harnesses

Hi, our small to medium rescue dog is growing beyond medium and as a little girl in the park said the other day: 'Hello massive dog' :) Drift's training is going pretty well considering his stray background and puppy age (depending on which park punter/expert, vet, dentist, TV talk show host...

Can anyone recommend any good harnesses? Any good leads and collars? I have been looking at some from Pets At Home, but there are none that seem good! :)