Easily defeated today. 13a. A measure of the maximum amount of work that can theoretically be obtained from a system? (6) e - -- g -. 25a. Festival of Irish traditional music, dancing etc? (6) - - - a - h. 26d. In various games, a situation in which one side fails to score or is left far behind? (5) - - r - h.
No, it's definitely fleadh - there's a big one in London every year - it's a big organised gathering like an eisteddfod. A ceilidh is much more intimate (though sometimes as loud!) and has too many letters.
Only half right, Safflower, I have lots of Irish connections - my surname is from Fermanagh and my mother came from Belfast, but I'm a Scot. Dundurn is a hill between Comrie and St Fillans.