Old barrier started to get vandalised (7)
I believe the answer is:
damaged
'vandalised' is the definition.
(I've seen this in another clue)
'old barrier started' is the wordplay.
'old' becomes 'aged' (similar in meaning).
'barrier' becomes 'dam' (dam is a kind of barrier).
'started' says to put letters next to each other.
'aged' put after 'dam' is 'DAMAGED'.
'to get' is the link.
(Other definitions for damaged that I've seen before include "Hurt" , "in poor condition" , "Sullied or harmed" , "Flawed, harmed" , "Harmed, injured or spoiled" .)