Thanks for the replies fellas..
Zapp - My options are not too bad. I could stay where I am (small private operator in SE England but not much flying and salary not exactly great), I also have a potential opportunity at Vista Jet with an EU base. The lure of HKG was a chance to live somewhere a bit more exotic than England (we aren't English so it's not home for us either), be in Asia and do some travelling to neighboring countries, and hopefully save a bit of cash out of what initially appeared to be a half-decent salary.
We're experienced enough expats, have done the sandpit thing for nearly 6yrs - no interest in going back, couple of years around the caribbean, also did some time in SIN but I wasn't with family so life in the world's most expensive city was not so expensive compared to what HKG would be.
I get the impression that 150k/month is not negotiable and factoring in the taxes just reduces it even more. Someone else mentioned how prices are constantly going up - that's also another concern so what is just 'only OK' today could be worth a bit less tomorrow.
Thanks again for the feedback - I appreciate it.