Blend still Champagne, say, around back of restaurant (10)
I believe the answer is:
intertwine
'blend' is the definition.
(thesaurus)
'still champagne say around back of restaurant' is the wordplay.
'still' becomes 'inert' (not moving).
'champagne say' becomes 'wine' (champagne is a kind of wine).
'around' indicates putting letters inside.
'back of restaurant' becomes 't' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'inert'+'wine'='inertwine'
'inertwine' placed around 't' is 'INTERTWINE'.
Can you help me to learn more?
(Other definitions for intertwine that I've seen before include "Twist together" , "Wire intent (anag)" , "Weave" , "Lace" .)