Orcadian maybe is left with her, heading off (8)
I believe the answer is:
islander
'orcadian' is the definition.
(someone from the Orkney Islands)
'is left with her heading off' is the wordplay.
'left' becomes 'l' (common abbreviation).
'with' becomes 'and'.
'heading off' means to remove the first letter.
'her' with its initial letter taken off is 'er'.
'is'+'l'+'and'+'er'='ISLANDER'
'maybe' acts as a link.
(Other definitions for islander that I've seen before include "Inhabitant of Man, for example" , "Inhabitant of Skye, say" , "Lesbian for one" , "Person inhabiting Aran, say" , "Rum person perhaps" .)