Thanks Bob, good move to let Avast know. Just a shame if they didn’t pick up on this since an awful lot of people are using Avast and it doesn’t look good when this sort of thing happens.
Craig, I re-installed Avast and then used Clear again to check that it had completed its actions as it should, and this gave the same result. Probably not wise for the uninitiated, like myself, to be fiddling around in the registry; shouldn’t need to anyway.