Scene of conflict sees site of historic abbey reduced to dust (12)
I believe the answer is:
battleground
'scene of conflict' is the definition.
(I've seen this before)
'site of historic abbey reduced to dust' is the wordplay.
'site of historic abbey' becomes 'battle' (East Sussex town).
'reduced to dust' becomes 'ground' (I've seen this before).
'battle'+'ground'='BATTLEGROUND'
'sees' is the link.
(Other definitions for battleground that I've seen before include "Place of military encounter" , "Area of conflict" , "scene of conflict" , "where action has taken place" , "arena" .)