Demolish V&A in frenzy (6)
I believe the answer is:
ravage
'demolish' is the definition.
(thesaurus)
'va in frenzy' is the wordplay.
'in' indicates putting letters inside.
'frenzy' becomes 'rage' (I've seen this before).
'va' going within 'rage' is 'RAVAGE'.
(Other definitions for ravage that I've seen before include "Act like a 6" , "Greatly damage, destroy" , "Lay waste, plunder" , "Wreak havoc upon" , "Devastation" .)