Just in case it of any interest to anyone - an article on the BBC website today about the history of buses used as political campaign vehicles here in the UK. Lots of photos of a wide variety of buses!:
Embattled buses - the ups and downs of an election staple
https://www.bbc.co.uk/news/uk-politics-39907963 (https://www.bbc.co.uk/news/uk-politics-39907963)
Jeremy