Hi
mogtalk had a discussion on this a little while ago, it turns out. The F560 is highly thought of, and also gets a good review in the tests of the Morgan Sport Vauxhall VVTI conversion 4/4 which is running on them.
the Avon CR6ZZ is £110 per tyre, more than twice the cost.
It's F560s for me. I'll let you know how they work out.
Nigel