Give one a posting to headquarters (7)
I believe the answer is:
station
'headquarters' is the definition.
(I've seen this before)
'give one a posting to' is the wordplay.
I cannot quite see how this works, but
'one' could be 'i' (Roman numeral) and 'i' is found within the answer.
'a' is within the answer.
'to' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for station that I've seen before include "Depot" , "Waterloo perhaps" , "Headquarters" , "eg Temple Meads" , "TV or radio channel" .)