Elaine Turvey as Eta, Hilary Dewhirst as Zeta ('girls of infinite charm' - to quote the Cast List), Roy Mace as Pi (his catch line was 'Oh dear, I feel thick' - spoken with a lisp) and Richard Goodswen as Theta.
 
The props were ingenious, for the time, and included a flying saucer that presented problems for the backstage crew in the confined space of Tomlinson Hall.  The 'computer' - or 'Electronic Wishing Machine' - was still around in a Hut 23 side room as late as 1964.