I flew BA LON-SAN back in 2001 and it was definitely a non-stop flight. I think it was from LGW (but not 100% sure). At the time, was London the only non-domestic flight to/from SAN (excluding Canada/Mexico)?
How do people recommend getting to SAN now? Rather than connect. is it just as easy to fly to LAX and drive down (made easier if hiring a car anyway which you probably need to do for San Diego). My only other trip there was a BA flight to PHX and an onward cheapo flight with Southwest to SAN.