The most common and most likely answer to this crossword clue is the 8 plus 4 letter word PORTLAND BILL
P
O
R
T
L
A
N
D
B
I
L
L
Buddy explains!
The straight part
We know that "area in Dorset" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case area in dorset = portland bill.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.