Thanks for your reply Alkymst, you have certainly done your homework a very detailed answer, and i agree that the skin punch is the most accurate way to test for small fibre damage or comparison.
My large nerve involvement was only picked up by an EMG, my own neuro done it, who is a PN specialist.
Perhaps when the healing process begins the small nerves may heal faster than the larger ones, or there is more to heal in the larger ones,i really don't know, i was lucky in that the cause was picked up very early when my PN started, so there wasn't too much damage to repair, had the cause been found a couple years later, i don't think i would be anywere near were i am now, but the healing process would have been slowly still happening though.
Brian