Thanks a lot for the info everyone. I have to blame myself somewhat for the theft, pretty rooky. I took my eye off my bag for a couple of minutes while playing pool in a bar. Though I am shocked and somewhat impressed at the thief's opportunism - it really was a momentary lapse from my usual vigilance! I'd left my passport in there as I'd worried it'd fall out of my pocket. Oh well, lesson learned the hard way.
I too am hopeful that given I'm only transitting at LHR it may never be checked? Potentially just by the gate agent?
I see Cw novice has said the 1hr renewal wont work. I could try the week long passport service, and nip home and get that during the transit. If I could put the application in today that'll be Wednesday UK time hoping to have it for Saturday - probably a long shot?
Alternatively yes I will test BA's sympathy or do a domestic TP run within the 2week extension for the remaining points. I may actually end up on 1490 TPs. Currently on 1090 and have 40+140+140+80 to credit if I'm correct that HEL-LHR is 80 (AA ticketed, AY metal if that makes a difference). The reason I thought 450 was that before the trip I had 690, and MMB said 840, so losing 80 for LHR-OTP gets 1450 (positioning on RFS). Is it possible that MMB is incorrect?
Just touched down at LAX so straight to the consulate, and will try and get the whole trip on the ETD. Not quite the stroll down Venice beach I had in mind but torching my own money will have to do! Oh and I am HBO by the way.