The most common and most likely answer to this crossword clue is the 2 plus 6 letter word CO AUTHOR
I've seen this crossword clue in Independent
C
O
A
U
T
H
O
R
Buddy explains!
The straight part
We know that "One helping with joined-up writing?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one helping with joined-up writing? = co author.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 CO AUTHOR mean?
CO AUTHOR noun- An author who collaborates with another to write something.
- To write something in collaboration with another author.