Gosh - what the Aussies call a big-headed Britisher! (6)

I believe the answer is:

blimey

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'gosh what the aussies call a' is the definition.
I can't tell whether this definition defines the answer.

'big-headed britisher' is the wordplay.
'big-headed' becomes 'b' (this might be a standard abbreviation I've not previously seen).
'britisher' becomes 'limey' (limey is a kind of britisher).
'b'+'limey'='BLIMEY'

Can you help me to learn more?

(Other definitions for blimey that I've seen before include "well!" , "Oath" , "Golly gosh!" , "Surprised expression" , "Good gracious me!" .)

I've seen this clue in the Evening Standard.

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