I quite agree that the rectangular green pellet tin is not true to the time period of the 1980 "Mercury" and will offend the purist Webley collector. In my defence, I can only say that I did not look at my project pistol as part of my Webley collection, and saw it as just another project to investigate obsolete British air pistol mechanisms. After all, my pistol differs from the originals in many ways, both from a materials point of view and how it is constructed. The case and fittings are for safe storage and just a bit of window dressing, and to me the rectangular tin is evocative of the late 1960's-1970 period when the design was first proposed, and I just like the look of the rectangular tin more than the round. So apologies, but I will be keeping the rectangular tin even though Troubledshooter has kindly offer to supply me with a more period round one.
Cheers
John