To answer a few questions
I agree that it is a gamble fitting the low mileage 2nd hand diff. Unfortunately there wasn't much in the piggy bank to do it any differently.
The plan was for a Q2 but the pricing, for me with my current financial commitments, was prohibitive.
The alternative was to fit a complete 2nd hand gearbox and but the risk would have been the same at double the price of the 2nd had diff only.
Price options were as follows all in ZAR
New gearbox from agent 33000
2nd hand gearbox 8000
New Q2 9800
New diff 8700
2nd hand diff (fitted) 4000
Symon, The gearbox it self wasn't damaged. If you are referring to the casing it was damaged but repairable.
Vasse, car had 164 435 km (102 770 mi) on the clock.