I didn’t get symptom relief before diagnosis, and indeed struggled to get any for some time after diagnosis, with GP surgery and hospital bickering about whose responsibility it was!
However, I think and hope I was just unlucky, and it really shouldn’t be like that. In principle, there’s absolutely no reason you can’t treat a symptom without a firm diagnosis of what’s causing it. What’s more, a GP should be able to do it - it doesn’t have to be a neuro. Unfortunately, some GPs are jobsworths, who refuse to take any initiative, and want directions in triplicate from the hospital about everything. But the only drugs that always require a neuro (and a specialist MS neuro, at that), are the disease modifying drugs, or DMDs. It is unusual (but not impossible) to be prescribed those in advance of a confirmed MS diagnosis.
However, almost anything for symptom relief does NOT require a consultant’s permission. GPs are free to use discretion and commonsense.