Firstly good news that your GP is on side - I’m so pleased
Secondly I’ll try to shed some light on what the MRI says but my knowledge is limited Karen maybe better placed here.
The central canal is the fluid filled space that runs the entire length of the spinal cord and connects with the ventricles (fluid filled lakes) in the brain. The fluid here is called cerebrospinal fluid (its the fluid thats usually drawn when you have a lumber puncture). Usually the canal is small or not that noticeable but what they seem to be saying here is the canal is prominent I think in the t5-t9 area (thoracic area). This can still be normal particulalrly if you have no problems or symptoms. However it can also be a sign of other things i.e syrinx (or syringomyelia). This is where you get a fluid filled type of sac develop due to a birth defect (like a chiara malformation) or pressure in your spinal cord, trauma etc.
You can have headaches, spasms and tightness in leg muscles, decreased sensation, weakness …etc as a result of this.
So it sounds like this is what they were quering but the spinal cord is difficult to scan so obviously they’re not a 100%. It certainly sounds like you need to see another neuro. I’m not an expert on syrinx but do the symptoms seem to ring any bells - they are similar to MS.
Didn’t the first neuro want to see you or do anything. I’m a bit puzzled - surely it may explain some of the symptoms you’ve been getting - though it is out of my medical knowledge remit so (hands up - I’.m no expert).
Hope that helps