Eat Cabbage!!!

More strange posters have been appearing all over the city. This is but one example:

Cabbage

Obviously this could be part of a Healthy Eating campaign. But where does this PLONK character fit into the equation?

I have been making extensive enquiries, but nobody seems to know exactly who he is, and lots of the information I have received has been contradictory in nature. Some claim that he is a local businessman who is trying to break into politics. Others claim that he runs a local cult whose practices include eating nothing but lentils and pulses, bathing seven times a day, and worship of mystical numbers and PLONK. The most outlandish story is that he is the son of a Mexican peon who skipped bail in Mexico several years ago for stealing some carrots from a powerful landowner and came to England to hide out and assume a new identity.

I am going to have to dig a little deeper and see if I can unravel this mystery.