Bloke receiving Communion finally in cathedral (7)
I believe the answer is:
minster
'cathedral' is the definition.
(minster is a kind of cathedral)
'bloke receiving communion finally' is the wordplay.
'bloke' becomes 'mister' (I've seen this before).
'receiving' means one lot of letters goes inside another.
'communion finally' becomes 'n' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'mister' going around 'n' is 'MINSTER'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for minster that I've seen before include "Large church (or cathedral at York)" , "Old monastic cathedral, such as York's" , "Large important church" , "Clergyman" , "Abbey or priory church" .)