Vault over line? A fair game (7)

I believe the answer is:

tombola

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'fair game' is the definition.
(game played at a fair)

'vault over line a' is the wordplay.
'vault' becomes 'tomb' (I've seen this before).
'over line' becomes 'ol' (this could be a standard abbreviation which I don't know about).
'tomb'+'ol'+'a'='TOMBOLA'

Can you help me to learn more?

(Other definitions for tombola that I've seen before include "Lottery in which tickets are drawn from a revolving drum" , "Fete game" , "gambling activity" , "it involves the luck of the draw" , "Lottery at fetes etc" .)

I've seen this clue in The Telegraph.

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