Eastern mate defends daughter, a spiky thing (7)

I believe the answer is:

echidna

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'a spiky thing' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.

'eastern mate defends daughter' is the wordplay.
'eastern' becomes 'e'.
'mate' becomes 'china' (cockney rhyming slang, mate is china plate).
'defends' is an insertion indicator.
'daughter' becomes 'd'.
'china' placed around 'd' is 'chidna'.
'e'+'chidna'='ECHIDNA'

Can you help me to learn more?

(Other definitions for echidna that I've seen before include "Spiny creature" , "Spiny Aus. mammal" , "Creature with spines" , "Toothless type" , "Australian creature" .)

I've seen this clue in The Telegraph.

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