The most common and most likely answer to this crossword clue is the 8 letter word LLANELLI
I've seen this crossword clue in The Times
L
L
A
N
E
L
L
I
More clues leading to the result LLANELLI
- Left way before trouble returned in UK town
- Poor girl left heart in Wales, coming back here?
- Left road over lakes and isle in Welsh town
- Left crook back on street somewhere in south Wales
- Latin woman in trouble reared in Welsh place
- Evil woman left heart in Wales back here?
- Scarlets, say, scrummaging, in two lines each, after 50-50
- Welsh town in trouble over imprisoning a little girl
- Left road’ll go to one Welsh town
- Town badly needing a change of direction, a girl admitted
Buddy explains!

The straight part
We know that "UK town" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case uk town = llanelli.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.