The most common and most likely answer to this crossword clue is the 10 letter word LAUNDRETTE
I've seen this crossword clue in The Daily Telegraph
L
A
U
N
D
R
E
T
T
E
Buddy explains!
The straight part
We know that "High street concern" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case high street concern = laundrette.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.
What does LAUNDRETTE mean?
LAUNDRETTE noun- A place that has facilities for washing and drying clothes that the public may pay to use.