Hi -wiski, thanks for letting us know the outcome.

CD/DVD is a really messy area for incompatibilities. Also some of the media is downright rubbish, and even varies from batch to batch with brand name stuff. A lot of it isn't made by the name on the box, it is outsourced and labelled. So, you get variations depending on what factory it was made at.

In theory, I would have thought that the ultra media should have at least played on the old drive (it certainly won't RW), but theory and what actually happens are very different

I have several customers with quite old drives so I have come across this problem before. They only do basic computing tasks and use the drives for backups, so they don't see any need to replace something that is still working.