BBM - I'd imagine that not wanting it divulged would be because OP's speed and balance on his stumps totally contradicts the DT's expert witnesses claim that he is barely able to walk on them, and can't balance unless he's holding onto something.
I am so sorry but I cannot agree with you. Either Derman or the previous witness explained that OP's proprioception would be extremely compromised in the dark, which to me makes absolute sense, and further it he or whoever also explained that OP was better able to balance when moving quickly rather than if going slowly, i.e. walking, which again makes sense if you think of it like riding a bike when it is much more difficult to balance when going slow than when going fast.
And unless you provide a link to where a witness says this, (btw Sam Taylor testified he was very unstable without his legs) from what I recall I think it is a gross exaggeration to say the DT's experts claimed OP "is barely able to walk" on his stumps. He can walk but clearly not as a normal person with feet, calf muscles, etc., and frankly with his size torso it seems impossible he could do so at a slow pace and keep his balance for long stretch without support every now and then on such narrow stumps which are some of the narrowest, if not the narrowest, I have seen on youtube videos of which there are quite a few and all have a better balance when moving quickly. And if you live with and care for two very disabled people as I do you would realise that "holding on" doesn't necessarily refer to physically grasping something, it can merely mean leaning against something, touching a wall here and there, etc.