Something I always wonder watching this and any other programmes about canals is how, when some of the tunnels on the canal system are over 2 miles long with only room for one boat, did they know - back in the day before the traffic lights they no doubt use now - did they know it was clear to enter, and that they wouldn't meet another boat halfway in? A system of tokens, like on a single-track railway?
I think Tim and Pru have a lot more help from the crew than they used to so the pressure is taken off Tim a bit. There are times when Pru looks completely dazed and of course the programme is heavily edited.
I don't think Pru is on her own when she's casting off, someone at least watches to make sure she has done it properly and to help her on and off the boat
A man would hop on the last boat allowed through and let those waiting go through and hop on the last one, back and forth, whilst a man at each end would stop boats going through until travelling man got off a boat
And later they used the same system as trains on a single track - the last boat through would carry a signal of some sort which would be passed to the last boat allowed through
It all developed over time - men signalling in a row, on the tunnel path if there was one, over the top if there wasn't; then travelling man on a boat; then the carried signal