To davids690. You are right about the fares from London to Philippines being a lot different to the other way round. Last year my sister in law visited us here on my invitation. I was amazed at the difference in the fare, considerably more expensive from the Philippines.
One thing I wanted to say also on here is that with regards to the BB privilege, although some think it's an automatic entitlement, you are supposed to actually ASK when you arrive to obtain the stamp on the passport, usually accompanied by BB written by hand over the stamp. On one visit here, I forgot and did not get my passport marked as a BB, on returning to London at Manila was accused of overstaying by one day, just pleaded innocence by saying I had misbooked the flight by reading the wrong date in my diary. Got away with it, but they did put a reminder in my passport so they take a better look at it now, hence me making certain I request the BB privilege when arriving.