Special Branch's home? Far end of Petticoat Lane (6)
I believe the answer is:
street
'lane' is the definition.
(I've seen this before)
'special branch's home? far end of petticoat' is the wordplay.
'special' becomes 'S' (common abbreviation as in Special Air Service).
'branch's home?' becomes 'tree' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'far end of' suggests the final letters.
The final letter of 'petticoat' is 't'.
's'+'tree'+'t'='STREET'
Can you help me to learn more?
(Other definitions for street that I've seen before include "Form of theatre" , "lane" , "Urban road" , "See 1 Down" , "Roadway" .)