I am looking for a Gordon Setter puppy and want to make sure that I buy one from parents with a low hip score but what would be acceptable as I understand that different breeds can have different acceptable scores! Am I correct?

The mean (average) score for Gordon Setters is 24, with the median (most common) score being 18. I would personally want both parents' scores to be below 18.
:)

Hopefully someone with Gordons on here can tell you. 

But if you don't find out on here, I asked my vet on a breed that I wasn't sure on and he looked it up for me.  Failing that, there must be a breed club for Gordons, either ring the Kennel Club or do a seach on the internet.

Good luck
Sandra