They will always hit you with roaming charges for a UK SIM abroad, the Plug n Talk is the absolute cheapest solution I have found.
What we really need is some serious innovation, development and network investment by the Globe and SMART networks in the Phils.
I'm guessing as I don't know the exact nature of their networks but I would not be surprised if most of the international telephone traffic out of the Phils was not on dedicated cables, I suspect it is being shared with the internet fibre for the most part but I may well be wrong.
Also a few years back the vast majority of IP traffic from the Phils was being routed through undersea cables going round the edge of the Pacific then across America then to Europe. There was a major cable breakage in 2006 that ruined internet bandwidth and phone connections for weeks (still worked but really slow for the net or very hard to get a call placed over the phone network).
Jim