A: What happens to the superannuation funding for a partner getting their NHS pension is a matter for agreement by the partnership.
I would recommend that a clause be inserted into your partnership deed if this is issue is not already covered by it.
The superannuation payment in your baseline is practice income. As a partnership, it is for you to decide how to apportion profit shares. I know of practices where this issue has gone to independent arbitration, but I do not believe that there is any hard and fast rule.
I do not know of any difference for PMS practices as opposed to GMS.