Thanks for the offer Simmo, but I've got a spare cush drive/sprocket holder and the bearing is fine.
In fact its also a spare wheel Im fitting the bearings to. Im only swopping cos I think this one has a less oval brake lining. The existing wheel bearings are not too bad (just that their unsealed and the wheels been knocking round the shed for ages) which is why I asked. I didnt want to start bashing and knacker them if it was going to turn into an awkward job when I have the alternative of just regreasing.
Also thanks for the reply GB500nz I've got the bearings now and will have go when I get round to it - now we have some sunshine at last, I'd rather be riding the bike than working on it!
Cheers
Mark