Richard, you seem to have some heavy hitters against the badge.You mention there wasn't a big cash outlay,so,other than the opinons from these experienced collectors/authors you only have the facts, which there doesn't seem to be much.. Sometimes though the fun is in the research..
I have seen, once, a Souval diamond badge copy used as a display,,the reverse was not like yours,,and I'm pretty sure the badge wasn't solid silver..Is there anyone that has a photo of the postwar copies they could show us here? OR photos of 'Mr.Steeles' Hollywood Military Hobbies pieces?

* Richard, Your letter from Souval, do they say they made a badge simliar to this, or exactly like this and it being one of theirs?. What is that marking on the pin? and are there any other markings on the back?

There are also the stories about an English master jeweler counterfeiter Barry Wittmond that supposedly made excellent looking diamond badges and other high ends like the 44 wound badge,,maybe this is one of his pieces?

Could be that you'll never know 100%,,know you'll keep trying though! ,G.