ZONE 1

Co Down, area of South and South East Co Antrim and eastern Co Armagh
ZONE 2

Includes the whole of Co Fermanagh, approximately the western half of Co Armagh and approximately the southern half of Co Tyrone.
ZONE 3

North Tyrone and County Derry/Londonderry (west of the Bann)
ZONE 4

Includes the majority of Co Antrim and a small area to the north east of Co Derry/Londonderry