Wow, thanks Persephone, for your prompt reply... So many questions.
No, the vet did not offer anything. She did check the area extensively and found nothing out of the ordinary. Not even redness.
I find she mostly itches when she sees us. She does itch on the odd occasion as I look out the window, but most of the time, when excited.
Someone did suggest that she may be alergic to a plant in our garden, but as we have an extensive range how does one find out?