Caledonian revolutionary had to be frustrated (8)
I believe the answer is:
scotched
'be frustrated' is the definition.
(I've seen this before)
'caledonian revolutionary had' is the wordplay.
'caledonian' becomes 'scot' (I've seen this in another clue).
'revolutionary' becomes 'Che' (Che Guevara the Marxist revolutionary).
'had' becomes 'd' (I've seen this in other clues).
'scot'+'che'+'d'='SCOTCHED'
'to' is the link.
(Other definitions for scotched that I've seen before include "Frustrated" , "Put the lid on" .)