Cold Scottish island toured by a dog expert (10)
I believe the answer is:
aficionado
'expert' is the definition.
(I've seen this before)
'cold scottish island toured by a dog' is the wordplay.
'cold' becomes 'C' (eg on taps).
'scottish island' becomes 'Iona' (island of the Hebrides).
'toured by' is an insertion indicator (tour can mean to go around).
'dog' becomes 'fido' (I've seen this before).
'c'+'iona'='ciona'
'a'+'fido'='afido'
'ciona' put into 'afido' is 'AFICIONADO'.
(Other definitions for aficionado that I've seen before include "Admirer" , "Expert person" , "Devotee" , "Informed enthusiast" , "Fan; enthusiast" .)