I think it's likely to be completely legit.
A search on google for the phone number as 07986 648071 reveals....
She has a facebook page as "Orange Dreams" same logo as the Gumtree advert.
Phone Number: 07986 648081. Duties undertaken: Appointment support, Cleaning, Domestic duties, Help with communication/letter reading, Ironing, Massage, Meal preparation, Parenting duties, Pedicure/Manicure, Personal care, Pet care, Shopping, Social Engagement, Transport provision, Walking. Contact Email: Click ...
I would save you hard earned!