G'day moweasy,
Good news about the drive! A win is a win!
The cutter? Mmmmm,
My instant thought on reading your description is that the spindle bearings that support the cutter disc are collapsed or some other significant issue with the spindle mounting etc. But that is only a theory. Photos, as always, are a the thing here.
Try grabbing the cutter disc and try giving it a good solid wriggle up and down to see if there is play in the bearings or some other problem. Best done with the cutter disengaged so your not fighting the belt tension.
Otherwise, photos
Cheers
