Old carriage office memo and article on hire purchase going all way the back (7)
I believe the answer is:
phaeton
'old carriage' is the definition.
'phaeton' can be an answer for 'carriage' (thesaurus). I am not sure about the 'old' bit.
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for phaeton that I've seen before include "4-wheeled carriage" , "transport" , "Coach" .)