I had it on the brainpan that it had been credible, but I was going off of recollection. According to a quick Google, it sounds like the allegation was made, Hutton has denied it (with the counterclaim that the accuser has a history of trying to blackmail him with this false narrative). No info I could find on whether anything had been proven, much less if either party had filed lawsuits and the like. Either way, it does look like Hutton is losing job opportunities over this.
Hustle wasn't a British remake of Leverage (or vice versa). Each was their own thing made independently that just happened to air around the same time and have a similar premise (as I recall, the Leverage crew were basically a Robin Hood group, while the Hustle characters were more or less solely out for themselves and just happened to target corrupt people). Now, there is currently a Korean remake of Leverage running. So far as I know, it doesn't have an English broadcast, but, according to the summaries I've seen, it is pretty recognizable as being a new take on it (the new characters have similar backstories and roles to their American counterparts and all that).