Large composition by an English composer (5)
I believe the answer is:
elgar
'an english composer' is the definition.
(I've seen this before)
'large composition' is the wordplay.
'composition' is an anagram indicator.
'large' is an anagram of 'ELGAR'.
'by' acts as a link.
(Other definitions for elgar that I've seen before include "Out of the strange glare comes an English composer" , "Glare strangely at the English composer" , "Glare critically at the British composer" , "13 composer, 1857-1934" , "[NIMROD] 's creator" .)