No experience of those two, but here's a link to a third provider

http://www.tr-register.co.uk/forums/index.php?/topic/37126-dunlop-alloy-wheels/?hl=dunlop

6th posting from the top tells you where he bought them!

Malcolm T
1966 +4
1957 TR3
1963 TR4
1983 LR 110
1985 Robin Hood 2.0l