You will also be expected to pay for everything at the restaurant too, even if ten people join you.

The exchange rate, even though not the best at the moment at 67 PHP to the £, will still allow you to "look after people" and buy presents.
It is quite hard to understand if you haven't been there, but you will experience poverty that you will not see in the Midlands.
You will be talked about if you are not generous.
I am not saying that you have to be foolish with your money but certainly don't be stingy.
Besides, if you are getting married on this trip there you should prepare for these costs........