The one non-Sassenach in Berkshire? (5)
I believe the answer is:
ascot
'in berkshire?' is the definition.
(I've seen this before)
'the one non-sassenach' is the wordplay.
'the one' becomes 'a' (a thing is one thing).
'non sassenach' becomes 'scot' (I can't justify this - if you can you should give a lot more credence to this answer).
'a'+'scot'='ASCOT'
Can you help me to learn more?
(Other definitions for ascot that I've seen before include "Royal race meeting venue" , "Necktie with wide square ends" , "Coats (anag) - racecourse" , "course without any fences!" , "Broad necktie" .)