Interestingly, BA seem to do things differently sometimes.
Recently registered for the triple miles promo and flew LHR - DEL - LHR in J . The bonus miles for the promo posted immediately after the outbound trip, before the return !!
Flew on Feb 6 to Del
On Feb 7 - 2 items posted
7296 miles for the J trip (inlcuding silver bonus, cabin bonus)
30233 miles for "Special Promotion"
Returned on Feb 10 and on Feb 11 got another 7296 miles posted
I know the miles were there on Feb 7 because I logged in to check while in DEL
Also, I haven't quite figured out how they got to 30,233 miles, shouldn't it be 4 X 7296 = 29184 ? Not that I'm complaining.