Forgive me for rambling a bit, I promise there is actually a point....
Another show I'm very, very fond of is The Goodies. In this show, you'll find lots of gags reused over and over again, particularly throwaway sight gags. Same ones, over and over again. And they got away with it, and were awesome, and the audiences ate it up for a decade.
But, that show was made in the 1970s. There was no means of re-watching an episode once it had aired unless you lucked into a repeat, so you could get away with recycling gags blatantly. In fact, re-using an old gag that worked was doing fans a favour, because they had no opportunity to re-experience the pleasure of the original performance.
But, that doesn't work with modern programs. The audience can and will record it ourselves, download it, torrent it, Youtube it, mash it up with My Little Ponies, make demotivators out of it... and relive the good bits over and over again. So today's program makers don't have the luxury that the Goodies had in being able to mine their back catalogue.
I laughed at 'penis' and 'arse biscuits' on the side of the Silverston car, and the lesbian hats on the rear wheel drive ice race cars, and the various other times it's been done. And the British Muff was funny, in itself... but since it's not a new joke and a lot of people saw it coming, I don't think it was worth spending all that time on the train when they could have been off doing car stuff which could have generated some genuine, unscripted humour.