Welsh factories abandoned directly (2,3,4,5)
I believe the answer is:
as the crow flies
'directly' is the definition.
(thesaurus)
'welsh factories abandoned' is the wordplay.
'abandoned' indicates anagramming the letters.
'welsh'+'factories'='welshfactories'
'welshfactories' anagrammed gives 'AS THE CROW FLIES'.
(Other definitions for as the crow flies that I've seen before include "taking shortest route" , "By direct route" , "How rook moves" , "move in a straight line" , "Directly" .)