Fine when spies are providing front (6)

I believe the answer is:

fascia

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'providing front' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.

'fine when spies' is the wordplay.
'fine' becomes 'f' (abbreviation).
'when' becomes 'as' (eg 'when I walked' means 'as I walked').
'spies' becomes 'CIA' (Central Intelligence Agency).
'f'+'as'+'cia'='FASCIA'

'are' acts as a link.

Can you help me to learn more?

(Other definitions for fascia that I've seen before include "Flat surface (archit.)" , "Surface over shop window" , "Board above house or shop" , "Car dashboard" , "Shopfront signboard" .)

I've seen this clue in The Daily Express.

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