Interesting film. Did not realise that so many castles had caves beneath them. The language was difficult to follow especially as the cefax ran out half way through. The title "Ulaidh faoi thalamh" was interesting. Translates as Underground treasure in both Welsh and Irish and Scottish Gaelic.
rhychydwr1 - not sure if you have seen Andy Mcinroy's Antrim Sea caves project from a few years ago, he has a lot of good write-ups and photos on his website - http://www.andymcinroyphotography.com/sea-caves-antrim
Unfortunately, I don?t have any Irish but the subtitles worked fine the whole way through for me on the IPlayer last night