The most common and most likely answer to this crossword clue is the 6 plus 7 letter word STATIC CARAVAN
I've seen this crossword clue in The Times
S
T
A
T
I
C
C
A
R
A
V
A
N
Buddy explains!
The straight part
We know that "holiday accommodation" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case holiday accommodation = static caravan.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.