To be honest, I think this is a bizarre way of doing things. Maybe the GP is protecting their budget? If the MRI is negative for demyelination, but you still have the symptoms that prompted the scan referral, what will they do? Refer to a neurologist anyway? (See Cherry Trees experience!) If the MRI is positive for demyelinating lesions, what will they do? Again, refer to a neurologist.
The GP cannot diagnose MS. They can’t rule MS out either.
In fact they can’t diagnose or rule out any neurological condition. It seems irrelevant whether they have confidence in their skill at reading an MRI scan and/or a radiologists report on the scan.
Bloody stupid for them to order the MRI. (In my opinion.)
Is there any point in you seeing the GP again (or if it were me, I’d write to the GP - a nice paper trail helps sometimes!) and gently and sweetly ask for a referral to a neurologist. You can both thank and applaud the GP for referring for an MRI in advance, but state that given your symptoms it seems to make sense for a neurologist to be able to comment on the MRI scan, irrespective of the results of that scan. And then any further tests the neurologist thinks are important can be ordered.