What one on fiddle must do to be clear about situation? (4,3,5)
I believe the answer is:
know the score
'be clear about situation?' is the definition.
(to know the score is to be well-informed)
'what one on fiddle must do' is the wordplay.
I cannot quite see how this works, but
'one' could be 'o' (I've seen this in other clues) and 'o' is located in the answer.
'on' could be 're' ('on' can be mean 'with reference to') and 're' is present in the answer.
This explanation may well be incorrect...
'to' acts as a link.
Can you help me to learn more?
(Other definitions for know the score that I've seen before include "A conductor has to" , "as should an orchestral musician?" , "A Wimbledon umpire should" , "well-informed" , "Orchestra should" .)