Paul, agree that you are taxed where you are earning and therefore with your case you would not be liable for UK tax. Just wanted to make the point that it can be a grey area unless your company has set things up correctly and it does depend upon how long you will be out of the country and how often you will return. As long as you are out of UK for more than 183 days in one year and an average of 91 days over a 4 year period you will not be liable for UK tax (except on income derived in UK such as from property)
If you are still doing work in UK and deriving income from that work then you may be liable for UK tax. If you are over in Hong Kong full time then you would only pay tax here at a much lower rate than UK.
Basically if you work and derive an income from a country, that is where you will be liable to pay tax but individual cases may differ, especially if your salary is split with some paid in UK and some in Hong Kong which will start to make things complicated.
The tax man will make sure he gets his cut one way on the other

As we both agree, best to talk to a tax expert and make sure that everything has been set up with you company back in UK, you have declared your self as a non-resident for tax purposes and you are not breaking any laws.
See
http://www.inlandrevenue.gov.uk/menus/non-residents.htm and
http://www.inlandrevenue.gov.uk/pdfs/ir20.htm for loads more information