Old educational institution last to trial novel form of debate (9)

I believe the answer is:

polylemma

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'form of debate' is the definition.
I know nothing about this answer so I can't tell whether it can be defined by this definition.

'old educational institution last to trial novel' is the wordplay.
'old educational institution' becomes 'poly' (I can't justify this - if you can you should give a lot more credence to this answer).
'last to' suggests the final letters.
'novel' becomes 'Emma' (novel by Jane Austen).
The last letter of 'trial' is 'l'.
'poly'+'l'+'emma'='POLYLEMMA'

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I've seen this clue in The Times.

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