Oriental sort of bean these days unknown to British Isles (6)
I believe the answer is:
adzuki
'oriental sort of bean' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'these days unknown to british isles' is the wordplay.
'these days' becomes 'AD' (as in Anno Domini, after Christ).
'unknown' becomes 'z' (algebra).
'to british' becomes 'uk' (Great Britain).
'isles' becomes 'i' (this might be a standard abbreviation I've not previously seen).
'ad'+'z'+'uk'+'i'='ADZUKI'
Can you help me to learn more?
(Other definitions for adzuki that I've seen before include "Type of bean (Z, not S)" , "Small edible bean (z, not s)" , "type of beans" , "Bean plant" .)