Dutch auction on the repair robbie ,think we both should go do it ,and get strawbs in a bikini , would pay for thatAs said usually those concentric bearings are relatively easy to change as they're not right a tight fit on the shaft like some other bearings.
Two grub screws and knock the shite out of the collar with a taper punch and it'll come loose the plenty of p!ss in the shaft, perhaps a rub over with emery cloth and hay presto bobs your uncle it'll come off.