The most common and most likely answer to this crossword clue is the 7 letter word CHELSEA
I've seen this crossword clue in The Guardian
C
H
E
L
S
E
A
More clues leading to the result CHELSEA
- Rachel's eager to welcome these footballers
- Besides tea houses, where might you encounter The Blues?
- . Clinton’s issue with part of London
- Every South African golfer when cycling gets the Blues
- Radical Argentinian university associated with a London club
- Drink to pass round, if not getting the blues
- Church given more by leader of affluent part of London
- Sort of bun that’s different dunked in tea
- Revolutionary left main London area
- The 14 man with no piano, instead getting drunk (7
Buddy explains!

The straight part
We know that "Sort of bun" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sort of bun = chelsea.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.