That's possible Rob, but the filter was not required as a replaceable item unless of course it fell off or got damaged. The post war civy Flea didn't use the maze filter at all. However the post war civy ML did and they might well have been the Cooper made filter. God knows when either company started or stopped manufacture. Judging from what I've just learnt though. The 'Air Maze' filter is correct for both models during war time production. Ron

PS. a google search reveals that Coopers(combined with Fiaam) and Air Maze are both still leading companies in air and oil filtration, and Air Maze boast about 8 decades of production.

email (option): ronpier@talk21.com