And it was.
Fantastic! says I, format DVD and copy to it like a stick. Go back a step.
Having given up on saving photos from corrupt H-disc, mainly because I'd found various directories with thousands of photos on the new drive and decided they'd have to do...I then set about copying to DVDs.
All went perfectly - testing the DVD pictures from time to time. I then got near to full capacity - some 200 MB to spare. I was very careful about this. Then the DVD couldn't be read.
X a thousand.
When I first copied to the DVD, it had to close in a way that it could be read. Having added to it tonight, does it need some spare space to prepare it for future use, again. ie did I not leave enough space on the DVD?