Possible Clues:

• Central regions
• Road from Dublin towards Belfast, Donegal, plus south-central parts
• SECOND PART OF 20
• Counties in the centre of Ireland
• You won't seek high and low for them on the map
• Not very bright about estates forming part of the UK
• Central area first to dim lights on motorway
• Region is concerned about imprisoning bad lad
• Set up faintly luminous lights in the interior
• Turned up hazy lights in Birmingham area