Just to add an up to date note to this topic. I drove Cygnet through Standedge Tunnel this morning, and despite saying a couple of years ago that I wouldn't like to drive through myself, found it not nearly so stressful as expected, not least because of Fred Carter's expert guidance. He is really quite a smooth operator. (I had already been towed through twice, and driven through by Fred last year).
There is now no protection given to boats, and I used my own tunnel light, which was quite adequate. It took an hour and a half, with no more scrapes than one would aquire in any other long tunnel or indeed on a long lock flight. A 'shadow' drove along the parallel tunnel, meeting at the emergency adits, but we didn't stop at any point.
The plan is to install a communications wire along the tunnel (like an induction loop in concert halls?), and allow boaters to navigate the tunnel themselves, without a chaperone or shadow, but I must say that Fred's guidance probably minimised any contact made, and gave me the confidence to drive at the speed I did.
Mac
BTW, a horseboat is to be legged through the tunnel this Saturday - I must say I don't envy them, given the extremely uneven nature of the unlined sections.