Question Author
Just an update on this. I wasn't really reading the popup message thoroughly enough. My free protection is still there. What I'm being nagged for is a data protection add-on which, tbh, I don't need as I never do stupid stuff like opening suspicious emails/links or 'liking' stuff on FB.
It looks I'm just going to keep getting nagged to buy a product I don't need. Annoying, but there you go.