Dancer type set Bevan back (7)
I believe the answer is:
fonteyn
'dancer' is the definition.
(I know that Fonteyn is a dancer)
'type set bevan back' is the wordplay.
'type set' becomes 'font' (I've seen this in another clue).
'bevan' becomes 'nye' (I've seen this before).
'back' shows that the letters should be reversed in order.
'nye' reversed gives 'eyn'.
'font'+'eyn'='FONTEYN'
(Other definitions for fonteyn that I've seen before include "'Margot ..., prima ballerina (7)'" , "Dame Margot --, ballet dancer" , "Margot ..., iconic English ballerina" , "Danseuse" , "Margot ..., English prima ballerina" .)