Continually annoy, as it happens, old-fashioned society girl, on return (7)
I believe the answer is:
bedevil
'continually annoy' is the definition.
'as it happens old-fashioned society girl on return' is the wordplay.
'as it happens' becomes 'live' (as in live television).
'old-fashioned society girl' becomes 'deb' (short for debutante).
'on return' shows that the letters should be reversed in order.
'live'+'deb'='livedeb'
'livedeb' written backwards gives 'BEDEVIL'.
(Other definitions for bedevil that I've seen before include "Vile bed (anag.)" , "Cause problems for" , "Cause continual difficulties" , "Dog" , "Throw into confusion" .)