First made in 1949 and deleted in 1965, one authority says it was unchanged during its production run, another says it acquired some plastic parts. Whatever that was a hell of a run. From 1949 to 1954 the model number was 571, changed to 971 from 1954 to 1965. It's another of those where you cannot really be sure which one you are looking at. I guess if it has plastic wheels it is a late one.
I've had my hands on a mint in box No.571 which does not have the Coles decal on the counterweight which demonstrates that some had it and some did not.
Notes - Lattice Jib 2.4m Long. EMA (Electro
Mobile Airodrome) Twin-axled , four tyred electrically driven mobile
crane with 360 slewing, 2 ton 2.4m jib. One major development was the
non-rigid jib made of welded sections. This machine developed from the 2
ton Mk1 through Mk II, III, V, VI, and VII versions increasing
capacities up to the 6 ton Mk VII.
I would never have thought this was electrically driven
The leaflet in the box states that a 'smart' pull on the bodywork hinges it back to allow access to the winding gear should you need to re-string it - what a good idea!