Just bought a Planet X carbon road bike. It's got a Sram Rival groupset but i'm sure the casette is a shimano 12/25 which works fine. So, if a shimano groupset and sram shifters work together – does anyone know if a campag casette and sram shifters will work together I've got a nice set of campag wheels I would mind upgrading it with.

Hi,
Unfortunately not, the Shimano and SRAM cassettes work fine with each other, i tend to buy Shimano cassette for use with SRAM group sets because they are cheaper.
BUT Campag cassettes wont work, not entirely sure why, i have tried it a few times, and the shifting just goes everywhere, must be a slight difference in the teeth profile, and spacing.
Have you tried looking for a shimano freehub for your wheels, it took me a while but eventually got hold of one for some old Daytona Hubs, and it worked a treat.
Cheers
Josh…

Exactly wot he said. Different sprocket spacing and different fitting for the freehub.

Just get a shimano compatible freehub for the wheels – about £40