Leading journalist going over regimental HQ (5)
I believe the answer is:
depot
'regimental hq' is the definition.
(headquarters)
'leading journalist going over' is the wordplay.
'leading' becomes 'top' (both can mean first-class).
'journalist' becomes 'ed' (short for editor).
'going over' says the letters should be written backwards.
'top'+'ed'='toped'
'toped' reversed gives 'DEPOT'.
(Other definitions for depot that I've seen before include "bus terminus" , "Large storage site" , "Storage place" , "Storehouse or terminus" , "(Military) store" .)