Thanks for the early reply Dominic, but I don't understand why they still insist the maximum supported is 8GB.
This would have invalidated my Applecare support contract if I'd upgraded within that period.
It seems to me that they are just trying to make people upgrade their machines.
Since my machine is still very similar to the current low-end of the MB Pro range, there is no reason to buy a new one unless I want Retina, so I'm planning to get the 8GB upgrade. It'll help me on the few occasions when I'm running Windows under Fusion which seems to get slower with every release.
Can you foresee any software upgrade issues if I upgrade To 16GB?
Many thanks for your interest.