British Embassy or Immigration and Heathrow airport has got nothing to do with the CFO.
YOu'll only need to attned the seminar if you are married to a foreigner and moving abroad etc. I'm actually surprised and the same time you are lucky because no one stop you in the Immigration in the Phils airport, mostly if you don't have this CFO stamp on your passport they won't let you go to oyur flight.
No need to worry now.
