The most common and most likely answer to this crossword clue is the 6 letter word BOWMEN
I've seen this crossword clue in The Sunday Telegraph
B
O
W
M
E
N
Buddy explains!
The straight part
We know that "Some Londoners/chaps that pull strings/are involved in rows" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case some londoners/chaps that pull strings/are involved in rows = bowmen.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 BOWMEN mean?
BOWMEN noun- A man who uses a bow; an archer.
- The person, in a team or among oarsmen, positioned nearest the bow.