Pets at Home... hmm. We went to the Preston branch to get our first ever Guineas, however, as we couldn't get the hutch in the car, we decided to get one locally, as we knew of a place on the way home.
When we got to the place to get the hutch, the lady who runs it asked us where we'd got our Guineas from, and when we told her, she warned us that she'd heard of other people who had gone to PAH for Guineas and they all had mites. As the Guineas were still in the car, we took them in, the lady, who is a BIG GP fan, turned them upside down and sure enough, there were bald spots on one of the GP's fur - mites!
When we got the GPs home, we contacted PAH head office to tell them, and they said that the Guineas wouldn't have left the store without being given a visual check. They hadn't even done that! Head office told us to return them to the store, but we didn't fancy a 40 min drive to get some more, which might have the same mites anyway, as there was only one area where they all resided.
So, we told therm we'd take them to the vets, at PAH's expense, which they VERY grudgingly accepted, and months down the line, they still hadn't paid the vets bill!
So, be careful.