The cab floor had 9 slats which was increased to 11 and on the later issues and the towing eye had some minor modifications to the shackle, On the first issues the treads on the rear wheels were cut straight across the face of the wheel but were soon modified to diagonal treads. The final run was mistakenly fitted with wheels with a smoooth face that were intended for the Y11-1 Aveling & Porter Road Roller. This is a commonly faked variation but a close examination of the axle ends will reveal any tampering.
A few examples of the Allchin have also been repoted to have a steerable front axle and this is assumed to be a pre production variation that was not carried over to the regular issue. Note that the correct spelling is Allchin with two 'L's but on the endflap of the box the spelling is Alchin with one 'L'. The Allchin was deleted in 1965 after 9 years in production which is a very long time for any Lesney model.