Your GP is mostly correct. You said, <He refuses to refer me to a neurologist telling me they won't be able to help me any more than he can, and that the only treatment option is rest so there is no point. >

There is not much a neuro can do beside understand the report of an EEG or positive image from a CT or MRI. But neither a CT not MRI will show anything. A negative finding from an MRI or CT will not change your symptoms.

There is not anything that can be done to treat PCS. Individual symptoms can sometimes be treated, such as head aches, anxiety, etc. If you are opposed to CT radiation, you are likely reluctant to the experimentation with the various meds that commonly thrown at you to get you out of the doctor's office. Other than trying low doses of amitriptyline to help with head aches, rest and reducing stress is the best short term solution.

You can help yourself by learning ways to work-around your current limitations. This allows you to start to resume some sort of normal life. This in itself, can lower your stress levels.

A very good neurologist may be able to better explain your symptoms but most do not have the time to explain them. Most neurologists will dismiss you if your problem does not show up on a CT, MRI or EEG. Only tumors, bleeds (hematomas), aneurisms (arterial bulges), ruptured aneurisms, embolisms (clots) and epilepsy will show up. PCS does not show up on any of them. Non-symptomatic bleeds from a concussion are absorbed within the first week or so.

If you want a doctor's opinion of Post Concussion Syndrome, check out the books on PCS written by doctors who have lived through the experience. They will tell you far more than any doctors usual clinical experience.