Most of English town ultimately felt dated (3-3)
I believe the answer is:
old-hat
'dated' is the definition.
(I've seen this in another clue)
'most of english town ultimately felt' is the wordplay.
'most of' means to remove the last letter.
'english' becomes 'Old English' (Old English is an example).
'town' becomes 'dha' (I am not sure about this - if you are sure you should believe this answer much more).
'ultimately' indicates one should take the final letters.
The last letter of 'felt' is 't'.
'old' with its final letter taken off is 'ol'.
'ol'+'dha'+'t'='OLD-HAT'
Can you help me to learn more?
(Other definitions for old-hat that I've seen before include "On the way out" , "Trite, hackneyed" , "Out-of-date" .)