I have started a new thread as my symptoms are different to the other thread with the same name.
A CF card was inadvertantly formatted in a Canon camera, before the photos were downloaded.
A deep scan with Recuva finds the photos but all say preview not available. I proceeded and recovered them, but they all are unreadable or corrupt.
I have used a competitors product to sucessfully recover the photos.
My problem is sorted, but if Periform want to fix a huge bug, I am happy to provide any info I can.
A corrupt image is attached - sorry upload failed even though file size is 1.1Mbyte.