obgraham Thanks, followed your link, and Bob's yer uncle. (just for the hell of it, I tried various wordings again and drew a blank!)
I loaded it on the spare drive, and all seemed very professional. However, with AVG, I can turn it off in an instant. In the few minutes I've played with the MS offering, I can see no way to click it off quickly other than Settings - Real-time protection. And un-tick the boxes.