Type of necktie produced by a Caledonian (5)
I believe the answer is:
ascot
'type of necktie' is the definition.
(I've seen this before)
'by a caledonian' is the wordplay.
'by' says to put letters next to each other.
'caledonian' becomes 'scot' (I've seen this in other clues).
'a' next to 'scot' is 'ASCOT'.
'produced' acts as a link.
(Other definitions for ascot that I've seen before include "Tie or cravat" , "sporting event" , "course without any fences!" , "Royal race meeting venue" , "prestigious meeting" .)