docjames, since the above fares are only MNL (not MEL, SYD, BNE or DRW) to LHR, they may not be quite as much a loss leader as some AFFers might have thought at a quick glance. It's usual for Oz residents to concentrate on fares ex or to Oz. PR would have lower staff costs than QF but neither are immune to expensive fuel, leasing or purchase costs, landing fees and so on.
This link may make things clearer - the fares are 'all in', which is the equivalent of what we in Oz call 'all taxes and surcharges included' (note that the return fares will include the UK's air passenger duty, which is why a single fare ex MNL to LHR is at a greater than 50 per cent discount to half the return cost):
Philippine Airlines :: Fly to London
(As anat01 rightly suggests, the miniscule P550 - US$11.45 last time I was there - departure tax must be paid in either of those currencies - no credit or debit cards - prior to passing through immigration. There's a booth at which you queue to pay it. The staff give change, although I've only ever paid in pesos. If paying in USD, the change is probably in pesos). In contrast, the P200 departure tax from MNL domestically is now included in the ticket price, but at most if not all other Filipino domestic airports, often tiny sums down to about P40 are always manually collected.
jetlagger, you are correct but PR's B773s are a comfortable aircraft on which to travel. They have good J beds (not quite completely lie flat, which as always may be annoying to a taller person). There is lovely diving and snorkelling available in Philippines, although the better time to travel within the islands is from about 15 December to 15 June, which is outside the unpredictable typhoon season. MNL is more subject to typhoons than the central and southern islands. Weather in months like January and February is often terrific: pretty low humidity and down to a comfy 21 - 22 at night (although Westerners used to a temperate climate may prefer airconditioning, or having a sea breeze and ceiling fans).