The most common and most likely answer to this crossword clue is the 18 letter word JACK-OF-ALL-TRADES
I've seen this crossword clue in Financial Times
J
A
C
K
-
O
F
-
A
L
L
-
T
R
A
D
E
S
Buddy explains!

The straight part
We know that "Versatile sort" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case versatile sort = jack-of-all-trades.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.
What does JACK-OF-ALL-TRADES mean?
JACK-OF-ALL-TRADES noun- One competent in many endeavors, especially one who excels in none of them.