The trouble is, all this boils down to case law. Which, as the name suggests defines each individual situation at the time. There are few guidelines, and no rules which allows HMRC to rule each case as they see fit.
However, what I believe to be consistent is as follows. If your overseas based, have made a cut with the UK, are paid overseas (in foreign currency), have a permanent, full time based position, overseas then you should be ok. It goes without saying that you need to have left the UK for one complete tax year, and not to have spent 90 midnights on UK soil in any complete tax year.
The problems, and sometimes the stories, come from pilots who are paid in sterling, work for a British carrier and have the family in the Uk, but a home in France or something. If this is the case, clearly you are trying to avoid tax, and still have all your centre of interest in the UK.
Taxation is to do with the individual. If your meet the overseas, full time, permanent situation i've mentioned above, your family should be able to do what they like. Only if you don't meet the situation above, will they try to prove your interests are UK based.
I have to mention that this is my take on the situation, and I am no tax advisor although this is the advice I have sought regarding my personal situation.
Hope it helps.....
