No, it's definitely 'Sellers'.
I think I've worked it out. 'Wrong arm', as in wrong arm bowling (like your 'wrong 'uns', also cricketing term) and 'wrong arm of the law'.
Thanks for your help in leading me to it.
Sorry Pompolia I still think JMR27 is correct. Deliveries is plural and wrong un is a type of delivery. Peter Cushing is or was a well known actor but perhaps cushing doesn't fit in with other clues in which case I give in!