As Colm61261 said they definately don't cover you in the North.
This might be helpful:
7.1.1 Use of Trade Licences
The use of trade licences is important from a VRT perspective in the context of the
use of unregistered vehicles in a public place by an authorised person. Briefly, the
purposes for which such vehicles may legally be used in a public place include:
�� inspection or testing in the course of, or following, repair or modification;
�� delivery to another authorised person;
�� driving to a port/airport or to a place on the land frontier for the purposes of
immediate exportation/removal from the State;
�� demonstration to a prospective purchaser.
The times within which such vehicles may legally be used in a public place are:
�� from Monday - Saturday inc., and
�� between the hours of 6 am - 10 pm.
provided that a valid trade licence is displayed on the vehicles at all times while they
are being so used. Usage for purposes other than those mentioned above, or outside
of the times stated (i.e. on Sundays and Bank Holidays or between the hours of 10
p.m. and 6 a.m.), is permitted only with the prior permission of the Revenue
Commissioners. Such permission must be obtained in advance from the local VRT
Control Officer.