This is true. If I were the UK and I saw what the US considered as evidence in this case, I would strongly consider requiring the US to provide prima facie evidence going forward.

That said, I was more replying to the claims that dual criminality were not required. The UK still needs to find the acts themselves as illegal under UK law. I don't remember it being clearly so. Frankly, the released information I read coming from grand jury didn't even seem illegal to me according to US law.