Substitute monarch posed with Zulu (6)

I believe the answer is:

ersatz

'substitute' is the definition.
(I know that substitute can be written as ersatz)

'monarch posed with zulu' is the wordplay.
'monarch' becomes 'ER' (abbreviation for Elizabeth Regina, British Queen).
'posed' becomes 'sat' (sitting is a kind of posing).
'with' is a charade indicator (letters next to each other).
'zulu' becomes 'Z' (phonetic alphabet: alpha, bravo, charlie etc.).
'er'+'sat'+'z'='ERSATZ'

(Other definitions for ersatz that I've seen before include "unnatural" , "False" , "Artificial or synthetic, from German" , "'Artificial, not genuine (6)'" , "Imitation, not the real thing" .)

I've seen this clue in The Sun and The Times.

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