I've seen similar a few times, it looks like some Italian outfit organise a tour which includes Ireland a couple of times each year.
Bet you noticed each MH had a number between 1 and 20 or thereabouts on the top left corner of the back wall.
BTW a french tour company, Patrick Thellier Voyages, organise similar tours here each year also,
CLICKY to see one of their three tours of Ireland.