'Womaniser with band!' It's what they called Mozart (8)
I believe the answer is:
wolfgang
'mozart' is the definition.
(I've seen this before)
'womaniser with band' is the wordplay.
'womaniser' becomes 'wolf' (wolf is a kind of womaniser).
'with' means one lot of letters go next to another.
'band' becomes 'gang' (both can mean a crew of people).
'wolf'+'gang'='WOLFGANG'
'it's what they called' is the link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for wolfgang that I've seen before include "Austrian composer of 'Don Giovanni'" , "A famous German waltz god (anag) -- composer" , "Name of German boy" , "He was born 250 years ago" , "Mozart's first name" .)