Caledonian cost adjuster (4)
I believe the answer is:
scot
'caledonian' is the definition.
(I've seen this before)
'cost adjuster' is the wordplay.
'cost' anagrams to 'SCOT'.
However, I am unsure how this is indicated.
Can you help me to learn more?
(Other definitions for scot that I've seen before include "Stevenson was one" , "Native of northern Great Britain" , "Rabbie Burns, for instance" , "Northern member of UK" , "levy, once" .)