The most common and most likely answer to this crossword clue is the 7 plus 4 plus 4 letter word HUNDRED ACRE WOOD
I've seen this crossword clue in Financial Times
H
U
N
D
R
E
D
A
C
R
E
W
O
O
D
Buddy explains!
The straight part
We know that "Where friends played" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case where friends played = hundred acre wood.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.