Well as would luck would have it: https://www.ebay.co.uk/itm/143161401121

Send him a message as he doesn't have any listed at the mo, his are known to be good, he has options for both Diamond PCD and another type he prefers (cant remember what it was called now) that are much harder tips...

or make your own holder/spring and order the Diamond insert tips only :), the eBay link above will show you other sellers selling they same sort of thing as well...

:)