Thanks for the advice guys. I'd drawn a blank with eBay and the VMCC shop, and was about to try the guy JFerg recommended when a friend suggested Jeff Hunter Engineering in Hall Green, Birmingham. He takes a bit of getting hold of, but once I did I found he has the moulds to make rubber bits for just about anything. Cost for my grips was £20 plus £3 p&p. Below is a photo of the bike they're for.
Andy