Be of one mind about English silver, first (5)
I believe the answer is:
Here is my best explanation:
'be of one mind' is the definition.
(I've seen this before)
'about english silver first' is the wordplay.
'about' becomes 're' (regarding**).
'english' becomes 'e' (abbreviation).
'silver' becomes 'ag' (Ag is the chemical symbol for silver).
'first' says to put letters next to each other.
'ree' after 'ag' is 'AGREE'.
(Other definitions for agree that I've seen before include "Go well together", "Concur, acquiesce", "Arrive at a settlement", "Fit", "Be in accord", "Tally up", "grant", "share the same view", "Be of one mind" and "confess?".)