Girl seen between Rachel and Ena? (5)
I believe the answer is:
helen
'girl' is the definition.
I don't understand how the remainder of the clue works.
(Other definitions for helen that I've seen before include "Ship launcher" , "Was this the face that launch'd a thousand ships?" , "Legendary beauty of Troy" , "-- Mirren, English actress" , "Woman who launched a thousand ships?" .)