Extract from Doris Lessing's Land Surrounded by Water not Landlocked

I believe the answer is:

isle

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'surrounded by water not landlocked' is the definition.
I can't tell whether this defines the answer.

'extract from doris lessing's land' is the wordplay.
'extract from' indicates a hidden word (some letters extracted from the clue).
'ISLE' is hidden within 'doris lessings land'.

Can you help me to learn more?

(Other definitions for isle that I've seen before include "Prince Edward perhaps" , "Man's one" , "Piece of land in water" , "description of Britain" , "Skye, for instance" .)

I've seen this clue in The Irish Times.

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