I find that that usually the prices can be slightly cheaper on their UK site than on the Irish one which seems to be rounded up generously to their advantage. The rare time I'm buying from SD, I buy from their UK site using my Revolut card which gives a better exchange rate so the savings are worth it. Better the few euro in my pocket than in Mike Ashley's.
Have had two of the items cancelled so far for no stock mind you.
Won't be bothering with them again too much hassle for what are basically Penneys clothes with names on them.