Taking down and out to get £1,000 (6)
I believe the answer is:
noting
'taking down' is the definition.
('note' can be a synonym of 'take down')
'and out to get ps1000' is the wordplay.
'and' becomes 'n' (common abbreviation for 'and').
'out' indicates an anagram.
'get' means one lot of letters go next to another.
'psi000' becomes 'ing' (I can't explain this - if you can you should believe this answer much more).
'to' anagrammed gives 'ot'.
'n'+'ot'+'ing'='NOTING'
Can you help me to learn more?
(Other definitions for noting that I've seen before include "Paying close attention to something" , "Recording in writing" , "Seeing" , "Observing or taking down" , "Making brief record as memory aid" .)