I've never been a breeder, but I would think it to be strange , were you told this when you got Scruffers? It's a delicate subject.
If he was registered, a five year pedigree chart would give a significant amount of matching . The Kennel Club website may give the advice you are wanting . There are links to registered dogs and and tests their owners have declared.
It's pot luck what you get, lots of very nicely bred pedigrees on here, like mine, have health problems, but that's probably why we joined the forum. The vast majority of Cockers ,one of the most popular and numerous breeds in the country, are fine. The only issue would be not to breed him without proper advice.