I don't think anyone can give an answer for your question in all honesty.
There are just too many variables.
In very principle most of the population can live on less than £1500 per year.
The average salary is maybe P10,000 -P15,000 per year in Manila.
Depends where you will live, what you will eat, how much electricity you will consume
(air-con is so bloody expensive), how often you will go out. Do you smoke , drink, gamble etc you get the idea.
GBP 10,000 should be more than OK if you are sensible and to a certain extent live just a little native sometimes.
Have you spent time in Phils before??
How long??
Was it just holiday??
What did the majority of your money get spent on??