I did an ex-DUB to SAN via LAX in J for work about a month ago - it was booked on the advanced purchase fare which was around at the time, can't remember the fare code or if it's still available but the TP runs thread should have the info in it. It worked out at about £1000 cheaper than going direct from LHR (though this was for a big medical conference when the direct fares always seem to be hiked up).

Enjoy San Diego, a fabulous city and I thoroughly enjoyed my trip there!

James