Cambridgeshire cathedral (3)
I believe the answer is:
ely
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">cambridgeshire cathedral</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for ely that I've seen before include "'Isle' in Cambridgeshire" , "Cathedral city in East Anglia" , "Small city in Cambridgeshire" , "UK city" , "Cathedral city in Cambridgeshire" .)