Alison: "No dilation one year can be quite moderate the next, likewise symptoms and a syrinx. Perhaps regular scanning on a 2yr period would be a good idea? especially for breeding stock. This would give a little more genetic history to work with as well?"
This is something I've thought about as well. As far as I've understood to get grade A the dog may actually have a dilatation as long as it is under 2mm. Isn't it then possible that the dog would get a grade D when scanned a few years later, if it has a dilatation of 1,9 mm at the age of 2,5 years? What would then be better from a breeding point of view: a 2,5-year-old dog with a dilatation of 1,9 and grade A, or a 10-year-old dog with a dilatation of 2,1 mm and grade D? I'm still studying the matter, and am not quite familiar with all these gradings etc.
Luckily we have the possiblity to scan our dogs now in Finland. The scan costs 400€ including a BAER-test and the Cavalier club supports the scan with 100€, so the owner has to pay 300€. The club also invited the 6 most used studs and paid for their scan entirely.