The cockney kept her captive in the wood (5)
I believe the answer is:
elder
'captive in the wood' is the definition.
'elder' can be an answer for 'wood' (type of tree). I'm not certain of the 'captive in the' bit.
'the cockney kept her' is the wordplay.
'the cockney kept' becomes 'eld' ('held' - I've seen this in another clue - said with a cockney accent, dropping the 'H').
'her' becomes 'er' (I can't explain this - if you can you should give a lot more credence to this answer).
'eld'+'er'='ELDER'
Can you help me to learn more?
(Other definitions for elder that I've seen before include "Senior - church official" , "Senior figure; tree" , "Kind of tree or senior person in tribe" , "Church leader; tree" , "Tribal leader; tree" .)