I'm sure these are correct but would appreciate help with the parsing.....
17a Who might point out errors in Biblical book? A clergyman (9) - CORRECTOR
I can see the RECTOR part but where does COR come from?
20a Working at rear of house, as Cinderella was (3,4) - PUT UPON
I get that Cinderella was 'Put upon' but why 'Rear of house'?
25a After working, you're all black and blue ... and another colour (5,4) - ROYAL BLUE
Other than it's a colour I have literally no idea what's going on with this.