Hi Kat, that's it (link to my thread) thanks.
Dennis - for full info refer to Prof Liam Breatnach's translation of Uraicecht na Ríar because this is the major and most relevant work on grades of Poet and Bard. It's not an easy text to read because it's written for scholars in Old Irish rather than as a lay-person's book, but the info is there in translation from Old Irish to English.
Also Prof Fergus Kelly has some of this info in his Guide to Early Irish Law.
If you have access to an academic library, you will find these books in the Irish section or Celtic studies (depening on classification) or Law.
If you don't then you can buy them in Hodges Figgis in Dublin (I see you're in Kilmainham) or directly from Dias as http://www.dias.ie
(go to publications section and you can order on line there). Cost is EUR 30.