Reference arranged at St Emilion (11)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
testimonial
'reference' is the definition.
(thesaurus)
'arranged at st emilion' is the wordplay.
'arranged' is an anagram indicator.
'at'+'st'+'emilion'='atstemilion'
'atstemilion' is an anagram of 'TESTIMONIAL'.
(Other definitions for testimonial that I've seen before include "Character recommendation - tribute for service" , "Tribute or token of respect" , "A written character" , "special match" , "Character reference" .)