Again team is collecting uniform that’s surplus (7)
I believe the answer is:
residue
'surplus' is the definition.
(I've seen this before)
'again team is collecting uniform' is the wordplay.
'again' becomes 're'.
'team' becomes 'side' (both can mean a sports team).
'is collecting' is an insertion indicator.
'uniform' becomes 'u' (phonetic alphabet: alpha, bravo, charlie etc.).
'side' going around 'u' is 'sidue'.
're'+'sidue'='RESIDUE'
'that's' is the link.
(Other definitions for residue that I've seen before include "Something left over" , "Remains to be seen" , "grounds" , "Matter left behind after other parts have been taken away" , "Material left" .)