Men-only party in The Palace perhaps is the icing on the cake for one of those in The Park (5,4)

I believe the answer is:

royal stag

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'the palace perhaps is the icing on the cake for one of those in the park' is the definition.
I can't judge whether this defines the answer.

'men-only party' is the wordplay.
'men only' becomes 'royal' (I am not sure about this - if you are sure you should believe this answer much more).
'party' becomes 'stag' (stag party is a kind of party).
'royal'+'stag'='ROYAL STAG'

'in' acts as a link.

Can you help me to learn more?

(Other definitions for royal stag that I've seen before include "Ruminant" , "deer" .)

I've seen this clue in the Irish Times and the Irish Times (Crosaire).

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