Just changed the bearings in the rear hub and noticed the cassette has a couple mm play.
The cassette is very easy to pull away from the hub body.(like fall off)
any ideas or a link to a thred with clues to why
cheers

Did you replace the freehub bearing when you did the rest of the hub?

no they felt smooth so didn't think they needed to be changed

just changed them aswell,still got play.

Well the cassette will come off if the end cap is loose i.e. the cap has a rubber O-ring on the inside which grips onto the axle – as the lock ring covers the end cap you can easily pull the cassette off if the cap is a loose fit.

Also have you remembered to install the freehub spacer?

http://www.cyclistno1.co.uk/features/maintenance/hope-pro-ii-rear-hub-service.htm

If its just the cassette that is loose on the freehub body then do you need a cassette spacer (depends on what cassette is used) but I doubt this. Also is your lock ring on properly and you have all of the sprockets i.e. 9sp?