The fact they all seem to be Savage is rather interesting in itself, I can only guess S&P imported a batch of Savages from somewhere specifically for the project...

Any interesting markings on them, old proofs etc that might give us a lead??

love to see some pics of the No1 Mk3 and P14 if you had any, did you have then converted yourself?

As I recall the Ensign was the first of the type, (circa 1983) it used air cartridges that were the size of 12 bore cartridges with a grey plastic shell, a mate of mine had one, it went into the grinder during the ban unfortunately.

I have seen an air cartridge Walther PPK "type" pistol, no idea who made that one though...