Position of a new church at back of street (6)
I believe the answer is:
stance
'position' is the definition.
(stance is a kind of position)
'a new church at back of street' is the wordplay.
'a new' becomes 'an' (I've seen this in other clues).
'church' becomes 'ce' (abbreviation for Church of England**).
'at back of' says to put letters next to each other.
'street' becomes 'st'.
'an'+'ce'='ance'
'ance' put after 'st' is 'STANCE'.
'of' is the link.
(Other definitions for stance that I've seen before include "Attitude on the tee?" , "Deportment" , "Golfer's position for making stroke" , "Posture, standing position" , "Player's posture for making, say, golf stroke" .)