Ted's back, having an office in the station (5)
I believe the answer is:
depot
'in the station' is the definition.
(I've seen this before)
'ted's back having an office' is the wordplay.
'back' says the letters should be written in reverse.
'having' means one lot of letters goes inside another.
'an office' becomes 'po' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'ted' in reverse letter order is 'det'.
'det' enclosing 'po' is 'DEPOT'.
Can you help me to learn more?
(Other definitions for depot that I've seen before include "Storage base" , "(Military) store" , "Storage place" , "Toped (anag.)" , "Storehouse or main bus station (5)" .)