It seems likely that Joan is in fact watching "Are you being served in Australia?" - a spinoff featuring only John Inman from the UK cast. A total of 16 episodes were produced in two series, which aired in 1980 and 1981. At least three other Prisoner supporting actors appeared in the series, as Robert reported in PCBH Digest 1191-  "Actress Tracey Kelly ... appeared in "Are You Being Served In Australia" in the Miss Brahms part. Comedian Shane Bourne who had played several small roles in Prisoner played the cocky "Mr Lucas" part in the Aussie version of the sitcom. Christine Amor who played Jean Vernon in PCBH is cast as Miss Nicholls in season 2.