Interesting point on the CIMT test, I hadn't considered that. I'm not sure I've ever had a cholesterol test before, so that might be why it wasn't picked up. :-)

My GP seems to be saying the because I'm fit and healthy, there's no other possible diagnosis than FH given the high numbers. I was kind of hoping for a bit more investigation and perhaps some corroboration. I'm not sure what form that should take though - genetic screen perhaps?