The tune Monsieur Leclerc plays on the piano in the cafe is the show's theme tune.
The Royal Air Force biplane that brings the tailor into France is a de Havilland DH-82 Tiger Moth. Introduced in 1932, the Tiger Moth was the RAF's primary trainer aircraft during World War Two and became popular with civilian fliers after the war. In the early days of the war, several Tiger Moths were also used briefly for coastal submarine patrols. These planes had no radios, so they carried homing pigeons to send messages if they were forced down--a neat twist for 'Allo 'Allo! (1982) as both Pigeon Post (1984) and Savile Row to the Rescue (1984) feature homing pigeons.
In 1986 Carmen Silvera released a 7" single of the vocal version of the series theme heard here, on the First Night Records label (SCORE 4). Called "'Allo 'Allo", the B-side was a cover of "Under The Bridges Of Paris".
The only episode in the series in which Gordon Kaye isn't credited first, he comes second to Carmen Silvera the only other person to have first billing.