OK Elliemay
16a Frass (I think) F _ _ SS
Clue
Larval excreta (frass) frequently found on turnip (5)
I don't have Chambers - is RASS somethng to do with turnips?
20d - I have MASJID ....
Mosque servant (female) admitting Jesuits (6)
mosque (masjid) = maid (female servant) around SJ (JJ or JS I could understand - why SJ?)