Okay, your problem is different from the regular issue with the Aquadrive's where the grease comes out when the allen bolts come loose.
At 10 years without problems I think it's time you order an overhaul
kit. When you have received it, take the CV joint off and put it on a bench. Open it up, clean all the grease out and visually check the two joints for wear and tear. If they look good, wash all the old grease and dirt (metal particles too) out with kerosine/paraffin (it's the same stuff but called different around the world... lamp-oil is the same too) until it's 100% clean and dry. Then you put the new grease and parts
from the overhaul kit in.
Before you open it up, turn it with your hands holding it at about the same angles as when it's installed. See if you feel any hard spots. These should go away after cleaning
and re-greasing. If they don't go away, you need to replace the unit.
That is why I advise to ask for a quote for both an overhaul kit and a whole new CV joint. You can install the new one and check out the old one. If it's still good, overhaul it and store as a spare. The CV joint is a weak part of the transmission line so it's not a waste to have a spare (we do and overhauled each one already).
Also, check your thrust bearing for wear.