Great. #VirginMedia have changed their SMTP gateway config without warning, and now outbound mail has been idling in a queue here for the last 2 days, instead of being despatched on its way. Thanks for yet another avoidable screw-up, guys.
Outbound mail to go out via #VirginMedia still queuing since the 30th. Port 25 still being forcibly intercepted but no longer making connections, so can't do starttls...
Config change, no warning, so email hosed. (Yes, yes, I've been lazy and not bothered to bring my mail server out of the dark ages, but these things should be warned in advance.)