58a BEA Coach

[Idris]

The NAMC’s “Catalog of all Series Matchbox Models” (first edition) has an interesting entry at position 58-1a which is as Nick's variation codes 1, 2 and 3, but with even smaller GPW. Since Nick lists all models with 7.5 mm diameter wheels, this seems unlikely and this variation is not reflected in any of the other listings.
The AIM “1-75 Series Regular Wheels” catalogue (second printing, 1983) does not contain any unlisted variations, and neither does either Houghton’s “Definitive Guide to Matchbox Toys” (2007) or Stannard.
U.K. Matchbox did not cover the model.