The most common and most likely answer to this crossword clue is the 1 plus 13 letter word 5 LEVANT/UNISON
I've seen this crossword clue in The Guardian
5
L
E
V
A
N
T
/
U
N
I
S
O
N
Buddy explains!
The straight part
We know that "See Phil Page’s comment below. " is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case see phil page’s comment below. = 5 levant/unison.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.