7a "Poor rate for working US detective" (8) O - E - A - O - which may be OPERATOR but why?
6d "Adult gets into highly enjoyable duty" (6) T - R - F - which may be TARIFF but why?
16d "Standard went up by gum" (8) R - S - T - E - (no idea on this one!)
22d "Crib last part of exam and risk no end of reprimand" (6) M - N - E - which may be MANGER but why?