other series and many pantomimes. It Ain't Half Hot Mum regularly got audiences of up to 17 million. Shortly after making his first appearance in It Ain't Half Hot Mum, Knowles had a recurring role in The Rough with the Smooth in 1975 playing the Vicar. The series also starred Tim Brooke-Taylor, John Junkin and Richard Hurndall. At the same time as The Rough with the Smooth Knowles appeared as the character of Nigel in the series Rogue's Rock, starring Clive Morton and Knowles’ and Donald Hewlett. The next year Knowles went on to have a minor role in the film Spy Story starring Philip Latham. In 1977, Knowles featured alongside Hewlett again for Jeremy Lloyd and David Croft's second writing collaboration with the science fiction series Come Back Mrs Noah in which Knowles played the mathematician Fanshaw. Unfortunately, the series ran for only 6 episodes with some even going as far as to say that it is Britain's worst ever TV sitcom. The series has not been repeated in the UK but has in American where it was slightly more well received by audiences. Knowles continued his double-act alongside Hewlett in the 1984 eight part BBC Radio sitcom Anything Legal as George, a laid-off city gent. In 1986, Knowles appeared in the film The End Of The World Man playing Sir George. In 1988, Knowles played The Honourable Teddy Meldrum in Jimmy Perry and David Croft's last collaboration You Rang, M'Lord? which ran until 1992. The series was a success in Eastern Europe and especially in Hungary. In 2018, Knowles along with four other former cast members attending an event in Budapest with 900 Hungarian fans. In 1989, Knowles appeared in his only American film, Vampire's Kiss starring Nicolas Cage. Another film role came later that year when he voiced the Head of the Air Force in the animated movie The BFG, starring David Jason and based on the novel by Roald Dahl. Knowles has appeared as Norrington Byng in the children's television series The DJ Kat Show and alongside David Walliams in the comedy sketch show Walliams & Friend, playing the father of Jack Whitehall alongside Whitehall's real life mother Hillary. In 2021, Knowles appeared on British television for the first time in five years by being interviewed for the Channel 5 documentary Dad's Army: Secret Lives & Scandal. Others interviewees included Frank Williams, Arthur Lowe's son Stephen