John or Noel wandering round the East End (5)
I believe the answer is:
elton
'john' is the definition.
(musician Elton John)
'noel wandering round the east end' is the wordplay.
'wandering' indicates anagramming the letters.
'round' is an insertion indicator.
'end' says to take the final letters.
The last letter of 'east' is 't'.
'noel' anagrammed gives 'elon'.
'elon' going around 't' is 'ELTON'.
'or' is the link.
(Other definitions for elton that I've seen before include "Let on he's John, the singer" , ". . . . . John (musician)" , "..... Jonn (musician)" , "- John, British singer" , "Sir - - John, singer songwriter" .)