Cryptic crossword clue
Epistolary novel: badly written letters in yarns? I opt out this was pre-GCSE

The most common and most likely answer to this crossword clue is the 7 letter word O-LEVEL

I've seen this crossword clue in The Guardian
O
-
L
E
V
E
L

Buddy explains!

The straight part
We know that "his was pre-GCSE" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case his was pre-gcse = o-level.
The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.
This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.

Crossword Answer definitions

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