Managed to find a detailed set of instructions for removal, but this did involve editing the registry, which isn't something a non-techy person attempts without Extreme Trepidation. Thankfully, I used to be married to someone who is a techy person, and who very kindly came over yesterday evening and sorted it out. But I do wonder why McAfee didn't spot it.
In a continuation of foolishness, managed to set out this morning and got halfway to the station before I realised I'd left my season ticket in my other bag. So I have a few minutes to rant about viruses before the next train!
Also, a couple of pictures. I should really have chopped this japonica and this berberis before now, but it'll have to wait until the flowers-and-leaves combination is less breathtaking.

And in a Bug update... Outside, therefore happy...