Mate admitting turn-on now and then in security detachment (6)
I believe the answer is:
patrol
'security detachment' is the definition.
'patrol' can be an answer for 'detachment' (patrol is a kind of detachment). I am not certain of the 'security' bit.
'mate admitting turn-on now and then' is the wordplay.
'mate' becomes 'pal' (I've seen this before).
'admitting' is an insertion indicator.
'now and then' means one should take alternating letters (letters taken on a regular basis, now and then).
'turn'+'on'='turnon'
The alternating letters of 'turnon' are 'tro'.
'pal' placed around 'tro' is 'PATROL'.
'in' is the link.
Can you help me to learn more?
(Other definitions for patrol that I've seen before include "Be on duty on a beat" , "Reconnaissance unit" , "Move round and keep watch" , "Guard's regular walk" , "Part of Scouts troop" .)