It doesn’t help at all, as it’s just more anecdotal evidence, but I am also from the UK and I remember getting the non-holo Mew from a friend in a trade and I know he didn’t attend and league events or anything. At the time, I was just a kid and didn’t know the “proper” origin stories of all of these Black Star promos, so I didn’t ask this friend where it came from. I just knew I wanted it, and I think I swapped him the Moltres/Zapdos/Articuno jumbo promo for it.
That jumbo was another example of a different UK release of a promo as I believe it was a WB store promo to tie in with Pokemon 2000, but I got mine as a free gift packed in with and early issue of the UK “Pokemon World” magazine.
