So the stash likely dates from the late 1690s? Mary II ~1694 + ~2 years? http://news.sky.com/story/1044609/coins-builders-find-stash-in-irish-pub
The terminus post quem would be the date of the latest coin in the hoard. Given that no guineas of William III appear, a deposition date of the late 1690's is probable. However, I'm not sure what effect the great recoinage of 1696 would have on the circulating gold.
Seems like a bit of a later time than one would think that the gold would be buried - seems like it would have been planted ca 1690-1 and I still have to wonder if it was from the Flock of Geese that might have left a bit later.
One would imagine a if paymaster of Louis XIV (who gave financial aid to the Irish Jacobites) absconded with funds c.1690 -- a distinct possibility for a heist -- there'd be a Louis d'Or or three, no? Why ONLY English coins?