Hi Katy, I've followed a few of your threads and I'm truly shocked at the appalling treatment (or rather, lack of treatment) your daughter has been subject to. I don't possibly see how the doctors can be so sure of their diagnosis when so little has been done to exclude neurological or other physical causes.
I have been having bad headaches recently, probably caused by stress, we think now. I went to my GP, who did a whole series of blood tests to exclude the obvious stuff, called me back the next day and then sent me straight to a neurologist, who sent me straight to get a CT scan because sudden headaches can be symptomatic of haemorrhage or brain tumours. So I had the CT within 24 hours of first going to my doctor, and we knew from then on what we were dealing with.
So why was my experience so different from your daughter's? Possibly because I live in Germany rather than the UK. In Britain 'take a paracetemol and sod off' seems to be the GPs' response to most things. Your daughter absolutely needs an MRI/CT, and how dare they try to say that you have 'problems' when you are simply making the point that her treatment has been inadequate. No way is the NHS a gold standard - it's a fairly hit or miss pile of crap, to be honest.
Surely a private neurologist will see you without a referral. If not just come to Germany (only a semi joke, but flights easily available), where you can be seen by a specialist within hours.