I'm really excited about this SAN-LHR route. I live in SD and love visiting London and I hate layovers! I've got the BA visa (with the 100K promo) in my pocket as well.

I also like flights from SD that arrive in europe mid-day which makes hotel check in easy and allows you to get a nice night out on your first night. Even when I go to other European destinations I like using London (or Amsterdam) as a "hub".