You have to remember here that HMRC have the bat, ball and rule book in this game. They may play or not. There was a case some while ago where they argued that the rule book that they published was for 'guidance' only. The judge agreed. IIRC the guidance was about the '90 day rule'...and it's irrelevance!
Having said that....If you live and work abroad then you have little to worry about. When you moved abroad; Did you have a leaving party. Did you sell your car, or at least have ownership transferred to another. Did you cancel your golfclub membership as you clearly won't need it. Same for electoral roll. Why vote, when you care less who governs. Not still adding to an ISA are you. I'm sure you told your pension fund that you'd moved so that they could write to your new address. C/C doesn't send statements to a UK address I hope.
Do you visit family in UK for holidays a few times a year-fine. But if you visit UK for three or four days/midnights twenty or so times (60-80pa-non working) then ask yourself if you're living abroad or 'having a larf'. HMRC won't give a fig if you stay in UK for 90 days or 09 days if they don't think that you live elsewhere. They'll investigate your centre of life and if they consider it UK you'll pay UK tax. Bear in mind all this is about you, not your family.
Also how long do you envisage living abroad. Six months or six years. One is an extended posting, the other shows an intent to live abroad/stay offshore for a goodly time. If you're away more than five year I believe there's no CGT on anything that you may own UK and subsequently sell.
If you're living abroad, working for a foreign carrier but have a family/mortgage/car in UK then speak with Fry's. They're well up to speed on all of this and will make sure that you do it right.
UKplc is close to skint and if they can find/see easy pickings they'll chase you. Best to set things up properly before they come chasing.
S
PS. Domicile and residency, or more particularly non-residency are entirely different concepts that needs an expert to explain.
PPS. I'm not a lawyer/accountant but I've been in too many bars and listened to too many sad stories.