In partial answer to my question, after a preview scan, the Epson
preview screen minimizes, which I hadn't noticed. In the past it stayed
open and, after closing it, the scan window in PE was then useable.
Without closing it, status is as I originally noted. Still to check why
the Epson scan screen is automatically minimizing rather than staying
open until I close it. Will take a look at the Epson software.
Grandson returns this Sunday.