Graham I'm sorry, I copied a Link which didn't make it very Clear., Child rates are different, but it also applies to Adults, as can be seen below:

New rates of APD after 1st April 2015 compared with during 2014:

Lower (standard) rate Higher rate
2014 From 1.4.2015 2014 From 1.4.2015
Band A0 – 2000 miles £13 £13 £26 £26
Band B2000 – 4000 miles £69 £71 £138 £142
Band C4000 – 6000 miles £85 £71 £170 £142
Band DOver 6000 miles £97 £71 £194 £142
Loss to the Treasury of the amalgamation of Bands C and D into Band B after 2015
Exchequer impact (£m)

http://www.airportwatch.org.uk/air-passenger-duty/

There it gives a better idea, and it applies to Philippines Flights, and looks to be about £28 for Flights between 4000 and 6000, and £52 for flights over 6000 so if you booked your Flight before April 1st you can claim this Air Passenger Duty back. and for the rest of us, we can expect to see cheaper Flying