Hi, I am happy to report that I now have my 10mb!
You may remember that Virgin told me that my Ambit 120 was not compatible with the 10mb upgrade, so they sent out a new one, which I received 2 days early- an Ambit 256.
After plugging it in, a short activation call with Virgin and a few PC restarts, everything was up and running at 10mb.
Thanks to everyone who helped- (or read) my posts, I hope the information and outcome can be used to help someone who may come across the same or similar issue.
Dan