Hi, good luck getting your tier points and miles though!
I flew BMI 11 days ago, and had my BA gold number in the booking. I got all the normal perks, premium check-in and lounge etc, but nothing has yet shown up in my BA account.
When I emailed BA they said their systems are not due to be updated until end of May, and I should try to claim the points/miles after this date. I don't remember that anywhere in the FAQs. I can't use the "claim missing points" link as BMI are not even on the list of as a Partner Airline.
A bit of a poor response from EC in my opinion, i.e. nothing we can do try again in 3 weeks.