Gallery on board after controller returns to former position (10)
I believe the answer is:
reinstates
'board after controller returns to former position' is the definition.
I can't tell whether this definition defines the answer.
'gallery on' is the wordplay.
I cannot really see how this works, but
'gallery' could be 'tate' (Tate Modern, Tate Britain etc) and 'tate' is present in the answer.
'on' could be 're' ('on' can be mean 'with reference to') and 're' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Another definition for reinstates that I've seen is " Re-establishes".)