Not at all (I have an allotment in London). The rules are there because allotments are supposed to be for you to grow food for your own consumption, rather than

Not at all (I have an allotment in London). The rules are there because allotments are supposed to be for you to grow food for your own consumption, rather than as commercial small holdings. People sometimes break this rule and you will see a plot that is dedicated (say) entirely to onions. The sites aren't designed to keep livestock on either, and they are small enough that you have to be a bit careful with hives disturbing neighbours.