Ken, backed up by Len, makes a shelter (6)
I believe the answer is:
kennel
'a shelter' is the definition.
(I know that kennel is a type of shelter)
'ken backed up by len' is the wordplay.
'backed' is a charade indicator (letters next to each other).
'up by' says the letters should be written in reverse.
'len' written backwards gives 'nel'.
'ken'+'nel'='KENNEL'
'makes' acts as a link.
(Other definitions for kennel that I've seen before include "Dog house" , "Dog shelter" , "Dog's abode" , "Home for the dog" , "Canine boarding place" .)