Thanks, tried your suggestions but unfortunately, nothing works.

My wife has a newer version of FF and Opera; I have a sightly older FF esr version and r3dFox esr (advised that due to W7, am unable to update FF esr beyond what I currently have)

Also have the latest FF and Opera on the computer that we use to watch catch-up TV. Whatever I do, I receive the DRM message on everything.

What is strange, is we rarely watch Channel 4, but did so a few weeks ago without nay issue.