Only Connect S20E27 - Third Place Play-Off

Victoria Coren Mitchell hosts the quiz where knowledge only gets you so far – logic and lateral thinking are the vital extra ingredients.
It's the third place play-off, and the questions have grown suitably difficult. For example: Pelham and Hope, Curb and Fosse, Gag and Marley, and Snaffle and Geldof – what's the connection?