Great! Work back with Fleming in making fine instrument (5,5)
I believe the answer is:
grand piano
'fine instrument' is the definition.
'grand piano' can be an answer for 'instrument' (I've seen this before). I am not certain of the 'fine' bit.
'great work back with fleming in' is the wordplay.
'great' becomes 'grand' (I've seen this before).
'work back with' becomes 'po' (I am not sure about this - if you are sure you should believe this answer much more).
'fleming' becomes 'ian' (I've seen this in another clue).
'in' is an insertion indicator.
'po' placed around 'ian' is 'piano'.
'grand'+'piano'='GRAND PIANO'
'making' acts as a link.
Can you help me to learn more?
(Other definitions for grand piano that I've seen before include "One's three-legged" , "responsible for producing notes ..." , "Keyboard instrument" , "one getting tickled?" , "Large instrument with horizontal strings" .)