I dug my third PC out of the loft (a machine I keep with a clean install of XP and nothing else) – it comes in useful for flashing DVD Drives etc.
This machine failed writes at 53%! I then tried the cart on my other PCs and they too then failed at 53% – weird.
I then tried to write an unpadded rom and it wrote all the way to 100% (but of course wouldn’t run). I then tried a padded rom again and it too went all the way to 100% and then booted and ran in the VB.
It was a weird problem (Perhaps a Format Cart option in the writer program would have cured it) – However I don’t care what it was now that everything works. Off to play now – thanks again for helping to fulfill a 10 year old wish of mine.