If you permanently live overseas and do not practice in Ireland, it is not necessary for you to enrol on an Irish Professional Competence Scheme.
If you live overseas and practice in Ireland for any 30 days or more during the Professional Competence Year (May to April) then you MUST be enrolled on a Professional Competence Scheme
See:
Enrol on a Professional Competence Scheme
Medical Council advice for doctors practising outside the State