Hi Neil,
No, you will not use -
"N'est-elle pas?", on its own, for "Isn't she?"
It will be -
n'est-ce pas ?
e.g.
Martine, n'est-elle pas malade ? = Isn't Martine ill?
But
Martine est malade, n'est-ce pas ? = Martine is ill, isn't she?
Hope this helps!
