Lovely island castle (6)
I believe the answer is:
glamis
'castle' is the definition.
(I've seen this before)
'lovely island' is the wordplay.
'lovely' becomes 'glam' (glamorous).
'island' becomes 'is' (abbreviation).
'glam'+'is'='GLAMIS'
(Other definitions for glamis that I've seen before include "Village in Angus with castle where the Queen's mother grew up" , "Scottish castle, once Macbeth's" , "Angus castle, legendary Monster" , "Home of Macbeth and the Queen" .)