Hi
I think it best if I don't comment on individual breeders (though I do have a bitch of Lynwater breeding myself, primarily because I love the temperament that is produced by this kennel).
As far as FN is concerned, there is no specific test that will identify carriers for this recessive disease before they are used for breeding - a puppy can be tested to see if it has the disease but that's about it. As an affected pup will not reach breeding age, its the unaffected carrier parents which produce the disease. Thankfully, FN is now relatively rare & most breeders now just take care to avoid the lines that have produced cases in the past.
PRA is a different matter - the Cocker Spaniel Club recommends all breeders should eye-test their stock annually since this is a late-onset disease & dogs that have tested clear when young may develop the disease at a later date. Like FN, PRA is a recessive disease which means parents that are unaffected themselves can produce the disease in their progeny. The fact that parents & grandparents have tested clear in the past does not mean that the breeder can relax & not bother testing anymore - the gene that produces PRA can pass along the generations for years & not cause a problem until the time comes that a dog carrying the PRA gene is mated to a bitch also carrying the gene. At the moment there is no test available to identify these carrier animals & all a responsible breeder can do is to test their dogs regularly to make sure they don't actually have the disease. Unfortunately, for whatever reasons, some well-known breeders choose not to eye-test (along with all the commercial breeders). I leave it up to you to decide whether you think they are doing the responsible thing or not

Hip-scoring is a little bit different in that Hip Dysplasia has not been that well-researched in Cockers in the UK, though the evidence seems to suggest that the worst hip-scores are seen in solid-coloured Cockers (this is confirmed by the evidence from other countries where hip-scoring is compulsory). Many of the well-known solid breeders do now hip-score their dogs, though some do not. Very few particolour breeders hip-score as there is not perceived to be a hip problem in particolours.
Hope this helps!
Regards
Jane