Their bliss is shattered in the United Kingdom (7,5)
I believe the answer is:
british isles
'the united kingdom' is the definition.
The definition and answer can be both locations as well as being singular nouns.
Maybe there's an association between them I don't understand?
'their bliss is shattered' is the wordplay.
'shattered' indicates anagramming the letters.
'their'+'bliss'+'is'='theirblissis'
'theirblissis' anagrammed gives 'BRITISH ISLES'.
'in' acts as a link.
Can you help me to learn more?
(Another definition for british isles that I've seen is " UK and Ireland".)