Rugby Union name for Australian football (5)

I believe the answer is:

rules

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'australian football' is the definition.
(I've seen this before)

'rugby union name' is the wordplay.
'rugby union' becomes 'RU' (abbreviation).
'name' becomes 'les' (I can't justify this - if you can you should believe this answer much more).
'ru'+'les'='RULES'

'for' acts as a link.

Can you help me to learn more?

(Other definitions for rules that I've seen before include "instructions" , "See 7" , "Is king" , "Reigns" , "is supreme, OK?" .)

I've seen this clue in the Evening Standard.

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