Received a follow-up call from a chap named 'Stephen Ryan' who had quite a strong Asian accent, insisting he was with an O2 dealer known as Central Telecom. He was pushing some so-called "business tariffs" my way. Just saw a similar episode on BBC's Scam Interceptors! I've gone ahead and blocked the number. No time for this nonsense!

Since there wasn't a message left, I’m inclined to think it's a scam.

It seems like they're conducting some kind of survey, but no one seems to be picking up the phone.

Received a call from an unfamiliar number, supposedly originating in London, but I chose to ignore it. It’s most likely yet another scam or nuisance call, just like the countless ones I've encountered previously. I've put a block on the number and filed a report.