They’re still doing this. For some reason I am surprised. Have any Dopers done it? Jerome K. Jerome mentions someone walking on the bank and towing the boat. There is a short humorous description of “being towed by girls.” Perhaps folks walked more in the nineteenth century. 
I’ve never done it (never even been to the UK), but I have watched the show from a couple years ago where Griff Rhys Jones, Rory McGrath, and Dara O’Briain do it.
Oohhh, I just noticed your link has a quote from Dara at the top, only they spell his last name wrong. 