I design primarily for the Interwar and WWII periods, and in 1:100 scale for 15mm gaming.
These days I print models almost exclusively in resin, but wherever it is feasible I design with tolerances suitable for FDM as well.
The Covenanter was the direct ancestor of the famous British Crusader tank of WWII. Its rushed production, initial teething troubles and opposition in certain official quarters gave it a poor reputation, though in truth by the time the Crusader came to replace it, most of those problems had been resolved. Nevertheless, though a few were sent out to the desert, it never did see active service. It did do excellent service as a training tank in the UK though.
This model is designed for FDM printing, and the zip file contains both turret and hull in either one-piece STLs, or split-up models to be printed and then glued together. My experience has been that the split versions will return smoother results on the sloping panels, and better detail in the tracks.