I would just add that 'bothering to campaign' is much easier for those with a big part machine to back them, especially with industry or union money coming in... the smaller parties, and the independents (pace the Jury Team) simply may not have the resources to leaflet many thousands of homes... and a proper Green candidate may well balk at the paper and print wastage that will ensue if they do.

Better media coverage of the minority parties and candidates would help, I feel... but I do feel obliged to defend those who have not, for whatever reason, spammed your letterbox. 'Not bothering' may really not be a fair assessment. Sorry for any offence - that's my tuppenceworth.