Invaders of Rome (7)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">invaders of rome</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for vandals that I've seen before include "Destroyers of the Roman Empire" , "Destructive hooligans" , "Destructive types" , "They destroy or deface property" , "they cause destruction" .)