In Ireland the dunes are, in general, bigger. I'm no geography expert but I assume this is due to the greater exposure to the Atlantic. In addition, Irish links tend to have been built more recently. As a result, construction of courses through bigger dunes was possible. Environmental issues did not carry as much weight in Ireland also - presumably due to the fact that the need for income in some remote areas of Ireland outweighs environmental concerns.
In Ireland, wonderful links through towering dunes have been built in the last 20 years or so (Doonbeg, Ballybunion Cashen, Carne, Enniscrone, Waterville, Rosapenna, Ballyliffin, Tralee) whereas none have been built in Britain.
There is great linksland in Britain but courses will never be built there. The attached photos are of Braunton Burrows, a 5 mile long stretch of massive dunes in Devon. The two courses at Saunton skirt the edge of these dunes but 10 courses could be built here. Likewise, anyone who has stood on the 14th tee at Pyle and Kenfig and not thought what great courses could be built in the vast expanse of dunes on view is no golf lover.