What particularly appealed to me was “When we questioned why a marina in such high demand only had one shower, we were politely told that most of the marina’s visitors had all the facilities they could ever need onboard.” It answers my unasked question about St Katherine’s Dock which I walk through as I wend my way home .

As for working out the riddle of the canal, I’ll leave that to others more capable than I of doing the maths!