I've never seen that before. Just checked mine, and it's okay. If you have the Samsung Members app, then head over to the support section and tap 'Ask questions '.
Sorry, I can't think of anything else, especially if you're confident the handset is UK stock, stock firmware, with correct CSC.
The only other thing is, have you returned from abroad recently? You mention a VPN...are you sure it's totally disabled?
I'll keep digging and see if I can find anything. Hopefully, someone else might have an idea.