Dr O Ciardha's accent was pretty striking, though not very Craggy Island, rather more Cavanish (though I think he's from neighbouring Monaghan)
https://www.youtube.com/watch?v=h8fITzlPgA0
My Mother's family are from Cavan, and though their accents aren't anywhere near as strong as that, the phrasing is pretty dead on.
Regardless he seems to be an expert on 17th/18th century Jacobitism in Ireland, so I'd like to read that book.
The program itself was a pretty even handed, basic account of the siege which didn't bring anything new to the table if you've read much on the subject. A good introduction which is as much as an hour long TV program could ever manage.