10 speed Sram force cassette, on cosmics. The rear cassette has started really rattling on rough surfaces at speed. There is a spacer there, the cassette looks okay. No detectable play in freehub when cassette removed, but with cassette on there is a little play if you wiggle the big cog. Done up very tight.

Will adjusting the bearings on the non drive side make any difference? Done up pretty tight but doesn’t seem to make any difference?

Is the next step a new freehub?

You need the thick Mavic spacer and a thin steel spacer for 10sp.

There are kits on ebay, its easy to do and YouChoob videos make it all understandable.

Yep got that thicker spacer in, tried with a second spacer still movement. From googling it looks like the bush might be slightly worn. Seems you can buy just the bushing and replace to tighten it back up.

There is always a small amount of movement even on new wheels.If there is wear on the hub itself (anodizing worn) a new bush won’t make too much difference.
However, Hub Doctor is really good (and fast delivery).The bearing replacement kit (replaces bush) is really good and eliminates any play as it sits tight against the hub body.Have done a fair few for customers.
http://stores.ebay.co.uk/TheHubDoctor/Mavic-Freehub-Rebuild-Kits-/_i.html?rt=nc&_fsub=3232977016&_sid=1012926&_trksid=p4634.c0.m14.l1581&_pgn=2

Thanks for the advice. Shame those kits aren’t far off a price of a new freehub once you pay postage 🙁