Disorderly non-members knocking out some poor guy in changing room (2,4)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

An anagram (‘disorderly’) of N o N-ME m B e R s without an anagram (‘poor’) of ‘some’ – a reference to a children’s cartoon character who has adventures wearing various costumes from a fancy-dress shop, but who’s ‘normal’ attire includes a 7/15