I bet the ones that are left are only sized for dwarfs or giants, thats what usually happens, all the "normal' sizes get sold, and the left overs are reduced..
I am an XXL , so might pop down and get another pair,if any left, the ones I have are great, they are warm, have a reinforced backside an back of legs panel,for bank sitting,they seem waterproof and most suprising of all, fit me. I have worn them recently in sub zero temps and had no probs.
Compared to some "branded" fishing salopettes they seem better all around, and a quarter or less of the price.
Dave