Thanks. I'm still not sure why the clue ended with "you and me" since the expression is normally just "...(it's) all Greek to me", but I agree that BETA is the best answer. I am the one who first suggested it on another thread but then I started to have doubts. I should always stand by my first instincts.
I did wonder if this was something to do with the way words are pronounced in Ireland (RTE sometimes uses odd homonyms such as debt/death), but I couldn't come up with anything except Be ta could sound like 'be to'), but that doesn't really work