Bob Grant, playing bus conductor Jack, had actually worked in real life as a bus conductor in order to pay his way through RADA (the Royal Academy of Dramatic Art).
At the British box-office in 1971 the movie out-performed the James Bond film Diamonds Are Forever (1971) but this was only because the Bond movie did not launch until December whereas this picture had debuted in the UK in July.
When Olive is too heavy for the sidecar, the rear motorcycle wheel lifts up. The combination would not have tipped up as Olive was sitting over the side wheel and as there are only three wheels in total, there is no other way in which it could have tipped.
As the driver walks towards the cab after Stan puts the spiders in it, she is wearing boots. In the next shot, when she is feeling the spiders on her legs, she is wearing shoes.
Blakey, Stan's Inspector: 'What's the matter with you, can't you drive? eh? Oh my god, look what you've done! Quick, get in that cab, pull away, quick! Hurry up!