Do some evening work on board perhaps (4,3)
I believe the answer is:
iron out
'do' is the definition.
Although both the answer and definition are verbs in their base form, I don't see how they can define each other.
'some evening work on board perhaps' is the wordplay.
I cannot really understand how this works, but
'on' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for iron out that I've seen before include "Clear up (problems)" , "Flatten" , "Clear up (wrinkles in clothes or agreement)" , "Get sorted" , "Settle, put right" .)