See books covering county’s missing years? (4-4)

I believe the answer is:

long-lost

'missing years?' is the definition.

'see books covering county's' is the wordplay.
'see' becomes 'lo' (archaic word meaning 'look!').
'books' becomes 'nt' (New Testament).
'covering' is an insertion indicator.
'county' becomes 'glos' (abbreviation for Gloucestershire).
'nt' enclosing 'glos' is 'nglost'.
'lo'+'nglost'='LONG-LOST'

(Another definition for long-lost that I've seen is " Missing for some time".)

I've seen this clue in The Times.

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