Enniskillen / St Angelo and Newtownards both still have public transport airfield licenses ( pre-requisite for charter ops ) but fire cover is the main restriction.
St Angelo is Cat 1 but can arrange Cat 3* on prior request. Ards is, as far as I know, Cat 1 but has had on-site cover from International for special events.
Of course, pre-war Newtownards used to be the airport for Belfast and the DH.89s would approach up the Lough dragging their radio antenna above the water as a proto-GPWS
Unfortunately the water often continued up and over the runway.
*
up to about Do-228 Srs 200 size