
Yes indeed Cavaliers ad Charlies are very different, so my reply is for Cavaliers. You may be able to get breeder recommendations if you PM tooolz, or I can recommend the breeder of mine if you send me a private message. (I've had 3 Cavaliers from her and the first lived to 15.) Don't get stuck on distance -if you find a pup where everything is right, travel for it. Mine's just a pet but I'd have gone anywhere in the country for the right one.
When I lost my old Cavalier nearly 2 years ago I was determined to only buy a pup from parents that followed the protocols. So you want parents no less than 2 ½ years old when mated for the first time, and grandparents no less than 5, and all (as in all 6 dogs) still heart clear (as in no grade of a murmur at all). Then both parents MRI scanned for SM, and ideally grandparents as well -my dog has 3 of the 4 grandparents scanned and both parents. I would NOT assume a breeding dog or bitch was okay just because generations before them had been tested -not enough is known about the inheritance.
MVD is graded 1 to 6 and you only breed from dogs with no murmur at all so 0. 50 % of all Cavaliers have a murmur by the age of 5 and something like 98 % by the age of 10, so you're unlikely to avoid it entirely -although dogs do exist that never get one. The main things are to a) get them as late in life as possible b) get as low grades as possible. Badly bred Cavaliers will often get grades from 3-6 as young as 4, which is why you don't want to buy anything from a breeder that doesn't heart test their dogs every year.
If you go to the breed club website
http://www.thecavalierclub.co.uk/ you will find information and also a list of heart clear Cavaliers aged over 5.
http://www.thecavalierclub.co.uk/health/hearts/hearts11/hearts11_a.html There is currently no list of SM clear Cavaliers (the only list that exists just shows some dogs that have been tested, does not give results) but there are plans afoot for the KC to include this on their website in he not too distant future. Also have a look at the Golden Oldies pages
http://www.thecavalierclub.co.uk/oldies/gold_oldies.php -one page for dogs aged over 11 still alive (starting with the oldest -and it does give breeder and parentage). One list for dogs that lived to over 11 but has died -you will find dogs aged over 18 on both!