Understanding when to raise standard over harbour (7)
I believe the answer is:
rapport
'understanding' is the definition.
(I've seen this before)
'to raise standard over harbour' is the wordplay.
'to raise' is a reversal indicator (in a down clue, letters go up).
'standard' becomes 'par' (standard of play in golf).
'over' means one lot of letters go next to another (in a down clue, some letters go over others).
'harbour' becomes 'port' (I've seen this before).
'par' written backwards gives 'rap'.
'rap'+'port'='RAPPORT'
'when' is the link.
(Other definitions for rapport that I've seen before include "Close relationship with a common understanding" , "Empathy" , "Mutual harmony and affinity" , "Feeling of affinity and harmony" , "Close and harmonious relationship" .)