Lack of clarity (via road markings) about which of the two lanes on approach should be used to access the middle lane.
Even if there is a 'technical' right answer to this (? there is signage of left hand approach lane to 'Retail Park', the left hand 'exit' lane is straight on (and left) while the middle and right 'exit' lanes go right...) drivers are clearly confused, and use *both* the left and right approach lanes to access the middle 'exit' lane - resulting in traffic 'incidents' and potential accidents.
(Even if both approach lanes are 'allowed' to filter into the middle (?), clarity is needed)