You need a repair kit. Available from the usual suspects.
It contains:
1x new shaft,
1x new needle bearing (for inner end)
1x new bush (for outer end)- undersized bore, needs reaming
1x plastic grease retainer sleeve (bin it if you still have original steel ones in there, they don't warp or split)
Difficulties:
pulling the old needle bearing out (unless you have the right puller)
driving the old bush out
reaming the bush, aligned with the needle bearing (you need a piloted reamer)
Easiest method- take it to Greig @ Mini Classic, or Mini King.
