The most common and most likely answer to this crossword clue is the 1 plus 4 plus 2 plus 1 plus 3 letter word A TALE OF A TUB
I've seen this crossword clue in The Times
A
T
A
L
E
O
F
A
T
U
B
More clues leading to the result A TALE OF A TUB
Buddy explains!
The straight part
We know that "Swift’s bathtime story?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case swift’s bathtime story? = a tale of a tub.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.