This is a QR, which I really only use when the * hits the fan. I don't want my home made bodge to compromise my safety for the sake a 5$ part. I will just add, I don't have a problem with Slingshot, their kit didn't fail, it was me losing the part.
So the piece pictured is stamped, not cast or machined. That is a bit tougher to make. And you are right - If you get it wrong, you could have a dangerous issue.
Still waiting on Slingy..............crickets..............maybe I am down to looking at only Switch for my next kites.
Just an update. Alex from Slingshot USA has responded to my email, was concerned by my problem and is shipping a part to me free of charge from America. Great service from Slingshot, so I guess the weak link was the importer TKC UK.