I never heard of Jimmy Saville but I did immediately associate the outfit with a cult leader seeing this image since it is kinda the stereotypical "we gonna kill ourselves and go to space" type look. Maybe it would have hit better over on this side of the pond if they dressed like Marshal Applewhite. I think he'd be more well recognized over here.

Then again, if the fact they are a cult is super obvious in the movie then it's still wild.