As it stands now There wouldn't be a problem, yep they wouldn't like it, but were never keen on the lever release by Southern gun and I don't think it was just the price they didn't like.
As long as it complies to a Straight Pull, as BP points out regarding the L1A1.... had my doubts at first but there are plenty out there, a .22 Semi auto Bren would be the way to go but I'd hang fire till next month.......