Mad Monk tries to divide your church (4,7)
I believe the answer is:
york minster
'church' is the definition.
(I've seen this before)
'mad monk tries to divide your' is the wordplay.
'mad' indicates an anagram.
'to divide' is an insertion indicator (some letters create a division in others).
'your' becomes 'yr' (shortened version of 'your' in eg textspeak).
'monk'+'tries'='monktries'
'monktries' anagrammed gives 'orkminste'.
'orkminste' inserted into 'yr' is 'YORK MINSTER'.
(Other definitions for york minster that I've seen before include "Primate of England's seat" , "place of worship" , "Impressive church" , "Northern cathedral" .)