The NAMC’s “Catalog of all Series Matchbox Models” (second edition) does not contain any variations not already listed by Nick.
The AIM's “1-75 Series Regular Wheels” catalogue (second printing, 1983) indicates the existence of two diameters of knobbly BPW, variation codes 28-2d and 28-2e) being the smaller of the two. Can any Member confirm the existence on this model of BPW smaller than 10 mm diameter?
Neither Stannard nor Houghton lists any new variations.
U.K. Matchbox examined the model. briefly in Vol. 1 no. 4 (Jun. '77) p62, but does not give any variations not already included in Nick's table.
It should be noted that Nick needs information on which codes exist with the thin, vertical brace on the right-hand side between the two tanks.