Golf club filling in trap (1,3,1)

I think it could be either:

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1,3,1

r and a

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'golf club filling in trap' is the definition.
I know nothing about this answer so I cannot tell whether it can be defined by this definition.

'golf club filling in trap' is the wordplay.
'golf club' becomes 'wedge' (I've seen this before).
'filling' indicates the central letters (the letters which fill the word).
'in' indicates putting letters inside.
'trap' becomes 'rana' (I can't justify this - if you can you should believe this answer much more).
The centre of 'wedge' is 'd'.
'd' put inside 'rana' is 'R AND A'.

Can you help me to learn more?

I've seen this clue in The Telegraph.

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