The most common and most likely answer to this crossword clue is the 4 plus 3 plus 2 letter word ADAM HAD EM
I've seen this crossword clue in The Guardian
A
D
A
M
H
A
D
E
M
Buddy explains!
The straight part
We know that "perhaps, 6 on 23" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case perhaps, 6 on 23 = adam had em.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.