I have identified a series of toys called "Miniature Vehicles" that were made in Hong Kong. These items are manufactured in a soft plastic. For the purposes of cataloguing my collection, I refer to this series of toys as "Miniature Vehicles". This series of toys appears in green and brown card boxes, much smaller than the Matchbox style boxes. I believe they may have been manufactured by the same company that manufactured the "Polythene Miniature" series as the vehicles used are the same as some of the "Polythene Miniature" range — only the series branding differs.
Having said that, it is entirely possible that both were manufactured by a third party and merely branded and packaged differently, according to whichever client was contracting them to manufacture. Either way it has proven impossible to determine the company behind the issue of "Polythene Miniature" branded toys or the company, or companies, behind the issue of "Miniature Vehicles" [and "Miniature Vehicles 2"].