Problem solved! - It turned out to be a faulty RAM module. I have now updated 8.02 to 8.1 with no issue.
As suggested I ran memtest86+ and it noted that there were errors. I then changed the RAM with some spare I had from an old laptop and ran the update from within 8.0.2 and hey presto! It looks like the Revo3700 has some life left in it after all
Thanks so much for your help guys! You create amazing software and I'm grateful you take the time to help users out to solve our problems.
Kind Regards,
ceekdp