Jottings, not a part of an essay (5)

I believe the answer is:

notes

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

'not a part of an essay' is the wordplay.
'a part of an essay' becomes 'es' (I am not sure about this - if you are sure you should believe this answer much more).
'not'+'es'='NOTES'

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(Other definitions for notes that I've seen before include "Doh, re, mi, ..." , "Jots down" , "Stone with jottings" , "Observes; short comments" , "Memos; observes" .)

I've seen this clue in the Evening Standard.

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