Fur auction the British go in for (5)
I believe the answer is:
sable
'fur' is the definition.
(sable is a kind of fur)
'auction the british go in for' is the wordplay.
'auction' becomes 'sale' (type of sale).
'the british go' becomes 'b' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'in for' indicates putting letters inside.
'sale' enclosing 'b' is 'SABLE'.
Can you help me to learn more?
(Other definitions for sable that I've seen before include "Marten's fur - dark black" , "Black (heraldry); fur" , "Dark brown fur of the marten" , "Antelope, fur" , "Bales (anag.)" .)