12d) A mere python (anag) distressed some insects (11) H??E??P?E?A
15a) It helps you write letters to agitated clients (anag. clients?) (7) S?E??I?
Finally 17d) 7 down attempts to find food stores . (6) In fact there are 8 letters for this clue. Thought pastries but couldn't figure out why. P??T?I?S
Thank you all - finally got stencil before I saw it had been answered. I now know why pantries as 7d was God and Pan of course was a God. Much appreciate your help.