British character of old coming to one sultanate (6)

I believe the answer is:

brunei

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'one sultanate' is the definition.
(Brunei is an example)

'british character of old coming to' is the wordplay.
'british' becomes 'br' (abbreviation for British).
'character' becomes 'u'.
'of old' becomes 'nei' (I can't justify this - if you can you should believe this answer much more).
'coming to' is a charade indicator (letters next to each other).
'br'+'u'+'nei'='BRUNEI'

Can you help me to learn more?

(Other definitions for brunei that I've seen before include "E. Indies sultanate" , "Ill" , "Commonwealth member" , "It's sultan is immensely rich" , "Muslim state" .)

I've seen this clue in The Guardian.

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