So all is well!
Put the new bearing in, i put it in the fridge first, and it went in easily with the old one to whack on, i did shave the old one off all round with a dremmel so no worries with it getting stuck....
Put the new chain on, and riveted it, fun...
End result no play in the back end any where....
But STILL got this slipping/spinning sensation, went to do some overtakes tonight off roundabouts onto A roads, and giving it gas it goes but then almost slips, so might be clutch...
which is fun as never messed with a clutch, and plan to do an oil/filter change soon....