Ok, lets try and make sense of what the MOT examiner has failed it for:
Are the headlight lenses cloudy in anyway?
Is there condensation on the inside of the lenses?
If no then it has to be another cause
I also highly doubt you have left hand drive headlights fitted... It must have passed its last Irish MOT? If you haven't fitted LHD lights, who else in the past year?
Try and use the Irish MOT check website and type in your registration and chassis no: to get a full report of all the car's previous MOT passes, advisories and failures... See if anything comes up regarding the headlight beam in the past
Bulbs are probably the main culprit as already said, can be out of position easily.....But to be safe than sure, get a replacement set of bulbs and remove the front bumper and headlights themselves for a much better access. It isn't that difficult a task to do. Once you have the headlights removed, it is very easy to fit the bulbs in correctly in position.
Have you checked your automatic headlight adjusters? are they both moving correctly at the same time?
A common issue is when these adjusters is they can get siezed and start clicking during manual adjustment of the top plastic nut... Thus a test centre that is trying to do you a favour by attempting to re-align your lights have no recourse but to abort the attempt if they have siezed.
When refiting the headlights, try a penny washer in each of the bottom bolt holes behind the headlight brackets... This will raise the headlight slightly and then your auto beam hieght adjuster will work a lot better with a greater range of adjustment.