Hi and welcome.
You may not like the documentary, but it is actually factual and true. I am not sure where you have read about cavalier health, but almost every cavalier (over 90%) will eventually have MVD. The statistics show that about 50% will have it by only age 5 -- a catastrophic disease of old age in young dogs. This is a disaster for the breed and makes MVD the leading cause of death -- especially EARLY death -- in the breed. I think any of us with cavaliers for any length of time has lost a dog to this dreadful killer. I have lost two to MVD in 18 months.
Syringomyelia eventually affects at least 70% of cavaliers, going on a study of over 500 cavaliers. A fourth have it by just age one. Almost every cavalier has the skull malformation that causes it, squashing the brain into too small a space, which can cause serious pain on its own. So yes, I am afriad almost
every cavalier deals with some aspect of CM/SM as well -- the documentaries you mentioned were actually more conservative than the reality of the problem as the extent of SM was not then fully understood. Three of my five cavaliers I've had, that have been MRId, have SM. All have CM. That would be probably a typical result if everyone MRId their cavaliers.
You can get lots of real and TRUE health information at
www.cavalierhealth.org, including summaries on all research work on these health issues and others.
In my opinion, Pedigree Dogs Exposed was extremely important, and has educated puppy buyers, helped vets understand and recognise the condition in dogs wrongly diagnosed for years with back pain or allergies, and helped force many breeders to take these conditions seriously. There were of course a small core of breeders who have taken health seriously in the breed all along but many of these have a hard time moving forward when the old guard on the committees and the judging panels refuse to seriously work towards breed health.
I realise that as the breed is rare in Portugal, you probably are not all that familiar with this breed and its very serious health problems, but until Pedigree Dogs Exposed, there was widespread denial that SM was anything more than a very rare disease (some national breed clubs were stating until recently that fewer than 1% of cavaliers had it -- utter nonsense!), and while clubs paid lip service to working to eradicate MVD, the reality is that they did -- and still do -- very little that is concrete.
Perhaps this is because the breeders who run the clubs themselves generally do so little themselves towards promoting healthful breeding and fail to set a personal example. One can simply go look at the recent puppy registrations in the UK and see that a number of the committee members of the UK Cavalier Club are still routinely breeding dogs UNDER the health protocol age of 2.5 -- such a very basic, important protocol, but apparently not worth their time to respect it.
What I really hope is that some day, there can be a Pedigree Dogs Exposed that reveals that the breed eventually survives and thrives because the Kennel Club finally gets some teeth, or the government creates legislation, to enforce healthful breeding.
The only general documentary on the breed that I know of, is one that runs occasionally on Animal Planet, on various breeds including the cavalier.