In
Episode #5.2 (1981), Tom O'Connor told Des that
Wednesday at Eight (1976) was renamed to "London Night Out", as one of the editions had clashed with Burns Night in Scotland, causing the show to be aired on the Thursday in the region.
Such a story seems apocryphal as the series hadn't aired on Burns Night, but it's possible that it contained an element of truth that was exaggerated for comic effect. Tom's anecdote also negates the fact that both shows were at one point running concurrently, with the third series of Wednesday At Eight airing after the first series of London Night Out.