About an hour ago (and maybe still now), there was a BA 747 on the ground at San Diego. But it's completely the wrong time of day. It's implausible that today's arrival from LHR has landed 8 hours early so was yesterday's return to LHR cancelled? Or has this diverted from somewhere else? By the way, San Diego airport website shows that today's departure to LHR is cancelled but BA website suggested that it is not.