Hi,
In my opinion you cannot beat Cathay, and i certainly wouldnt go Doah way. Fly to Hong Kong, if you are adventurous you can do it so easily without long stays.
Fly out of Heathrow at 12.45pm arrive in Hong Kong at 7.30am the following morning. Wait in Hong Kong untill 9.10am when flight leaves for Manila and arrive at 11.10am, no need to mess with baggage as you are in transit at Hong Kong, to my mind the hassle free clean and less tiring way
Cheers,
Tim