Wow that is an amazing amount of information so I am very grateful!!!! I have her on a raw food diet (Natures menu - which comes in blocks and has nothing else added to it and she only has natural fish treats. I also add a dash of Yumega oil plus to her morning food which is 'a unique blend of Omega 3 and 6 oils from natural plant sources specially selected to help maintain a healthy, soft & shiny coat, nourish the skin and help with moulting'. She has been having this for about 4 weeks.
My issue being that the vet has seen her 4 times and not once checked her skin or carried out any tests - he just said to give her anti-histamines to try and stop the itching.
I think I will take her back and ask that she be tested for Atopy so that we can start some sort of treatment to ease her scratching.
It definitely sounds like an allergy (I was starting to think it was neurological!!)