Of course, being cynical, 29ac could be a ploy to void this puzzle and save �50 - times are hard !
Also 20d We always spelled this as OMIKRON in our Greek classes at school - but I see some dictionaries today spell it OMICRON - any ideas on which is most acceptable in 2009?
Although KAPPA is obviously used when the word is spelled in Greek, I was taught (a few centuries ago! ) that in English spelling it was OMICRON. I think this is the generally accepted form today also.