The cheapest route is either Manchester/Heathrow to Manila normally so it might be a good idea to stay in Manila for a night and catch a promo to Cebu.
A reply I made to a member last week who had the same problem
Just done a quick search and prices & times differ big time.
August 1st to August 22nd for instance....cheapest flights.
Manchester-Cebu £1,006 22hrs/28hrs
Heathrow-Cebu £1,028 30hrs/34hrs
Heathrow-Manila £649 21hrs/18hrs
Manchester-Manila £527 30hrs/43hrs
Just had a look on Tiger Airways website and flights in early August from Manila to Cebu are going for 499 peso's (+luggage) for a single journey.