Thanks for the responses!
Martin - I have the original HDD so I could upgrade the Bios whilst that is installed and then proceed with the upgrade.....at least that's the theory!
On your other response regarding the bootloader, I think I know what you are saying but I need to re-read it and review the link to work out exactly what you are suggesting. Something for the weekend I think!
Squirrel - I am a bit concerned about a BIOS flash, especially as the Sony site doesn't really provide much help on that. But it really does seem like the answer. I guess I need to start pestering Sony and Phoenix for the correct file to ensure I get it right.
Thanks again