I have just had a look at one of my Dubliners LPs. They credit Donegal Danny to Coulter/Martin. I have managed to find a couple of other songs mentioned in Folksongs and Ballads popular in Ireland (volume 4 - I've lost the other ones). They do credit Pete St John with The Rare Ould Times but if I'm reading their notes correctly, it appears that Limerick Your'e a Lady was written by Dennis Allen - they mention he had a hit with it and don't say that it was written by anyone else.

Jon