This is a puzzler as the setter seems to have changed his mind half way through how it is to be parsed, or changed the answer and forgot to rewrite the clue. .
If the def. is complaint, then score fits (Chambers: grievance, grudge)
rather than scorn (contempt)
The def. cannot be foot complaint which would have been corns . .
Looks to be another of RT's errors of which there have been quite a lot over the years
Strewth is probably cor with SE around it. But then why is foot included in the clue !
I am lost