Without any trouble as I go into English cathedral city (6)
I believe the answer is:
easily
'without any trouble' is the definition.
(I've seen this in another clue)
'as i go into english cathedral city' is the wordplay.
'go into' is an insertion indicator (some letters go into others).
'english cathedral city' becomes 'ely' (I've seen this before).
'as'+'i'='asi'
'asi' put into 'ely' is 'EASILY'.
(Other definitions for easily that I've seen before include "Simply" , "without doubt" , "Comfortably" , "Effortlessly" , "Very probably" .)