About an hour ago, I took the simplest option and disabled the service, so far, without any issues.
I also have an old HP laptop and an old Dell Zino, the latter connected via HDMI to our TV. Both went from Win7 up to Win10 without any serious issues. Neither have the headline program/service "Monitor Virutal Wlan Service" running. Perhaps I should see how things unfold over the next few days, often checking the services to see whether "Monitor Virutal Wlan Service" might have been started by some other program.
Thanks to Cliff S and Halasz for the suggestions. I will flag solved if all continues OK by the middle of the coming week.