When I put the disc in the Camera in Record mode, it takes a long timr trying to access it then comes up an error code, which the manual says signifies either "the disc is faulty. Use a compatible disc with your camcorder" or "the disc is dirty or has scratches on it (it doesn't)."
When I try to put it in Play/Edit mode, I receive the same error code and a message "Disc Error. Unsupported format."
I put a new DVD-RW disc in the camcorder, followed Set Up which formats it and it set as Video which is the procedure I always follow. I don't know how to make it VR.
I think the conclusion appears to be to use a technical expression the disc is knackered!

Thanks very much for your help.

Thankfully I have plenty of stills but there was some nice video footage on this disc.