If dog fouling on pavements is unpleasant, cyclists on pavements are dangerous, and illegal, yet the practice has become common recently, and not just in Mundford. Car parking on pavements is also illegal. See an article in the September 2016 issue of Connect, which goes into more detail.
Below are the relevant rules from the Highway Code:
Rule 64
You MUST NOT cycle on a pavement.
Rule 244
You MUST NOT park partially or wholly on the pavement in London, and should not do so elsewhere unless signs permit it. Parking on the pavement can obstruct and seriously inconvenience pedestrians, people in wheelchairs or with visual impairments and people with prams or pushchairs.