i think each country has been given a index/value so you can translate the English pay scale to which ever country your applying from..
i think for the phils that value is 3.2
so £39,999 / 3.2 is £12,500a yr in the phils, 12,500 *75(php to £) /12 (months) = 78k php a month
also you need £2,800 in cash to show as maintenance