BBC7's website says that the episode it aired this week as well as next week's episode are from April 1973, making this the first series of "Hello Cheeky".

"Hello Cheeky" is the 1970's radio series starring Tim Brooke-Taylor, Barry Cryer, and John Junkin.  BBC7 is airing it on Sundays at 21:30 (with a repeat on Mondays at 04:30).