In Season Two Episode One of Happy Valley, the mentor constable explains to the new recruit how helpful it is to have a good relationship with the receptionist, Joyce:
Oh, and get well in with Joyce, she knows everybody and everything, and she'll never see you fast.
What is "see you fast"?
What I tried: idioms.thefreedictionary.com (both see and fast pages).
The story takes place in West Yorkshire.
I wonder if it has something to do with fasting as in going without food.