Mates who mucked around a bit (8)
I believe the answer is:
somewhat
'bit' is the definition.
(I have seen 'A bit' mean 'somewhat' so perhaps 'bit' could also mean 'somewhat')
'mates who mucked around a' is the wordplay.
'mates who' can be anagrammed to 'SOMEWHAT'.
Though, I am not clear how the anagram is indicated.
Can you help me to learn more?
(Other definitions for somewhat that I've seen before include "To a certain degree - a bit" , "Rather, a little" , "To an extent, a little" , "To some degree, sort of" , "To a certain extent" .)