Set off and shot round borders of Savoie area (3,2,3)
I believe the answer is:
put to sea
'set off' is the definition.
I know nothing about this answer so I cannot tell whether this works.
'shot round borders of savoie area' is the wordplay.
'shot round' becomes 'putto' (I can't explain this - if you can you should believe this answer much more).
'borders of' suggests removing the centre.
'area' becomes 'a' (maths abbreviation).
'savoie' with its centre removed is 'se'.
'putto'+'se'+'a'='PUT TO SEA'
'and' is the link.
Can you help me to learn more?
(Other definitions for put to sea that I've seen before include "start on the drink" , "Sail away" , "Set sail" .)