How long do you have to be out of the country before you become non-resident? Are you legally non-resident when you leave the country or does it happen after a period of time?
@CiaranT has given you a good link on residence.
This is different to domicile.
Usually it is helpful if you give some indication of what your issue is, otherwise one can only be specific based on what you tell us.
Is your issue filing tax returns or what?