Way Essex town’s character is an aid to progress (8,5)
I believe the answer is:
stepping stone
'aid to progress' is the definition.
(I've seen this before)
'way essex town's character is an' is the wordplay.
'way' becomes 'st' (abbreviation for street).
'essex town's' becomes 'epping's' (town in Essex).
'character' becomes 't' ().
'is an' becomes 'one'.
'st'+'eppings'+'t'+'one'='STEPPING-STONE'
(Other definitions for stepping stone that I've seen before include "Aid to gradual progress" , "feature across stream?" , "Footrest in river" , "This may help one to make progress" , "means of advancement" .)