The most common and most likely answer to this crossword clue is the 8 plus 2 plus 6 letter word PROSPECT OF WHITBY
P
R
O
S
P
E
C
T
O
F
W
H
I
T
B
Y
Buddy explains!
The straight part
We know that "on the 23dn at 28" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case on the 23dn at 28 = prospect of whitby.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.