I find the guides to sections of a canal (for instance, from Worcester Bar to Kings Norton Junction) with the points of interest in between very useful especially with their distance guides. As the start and finish points are not always obvious on a map, it would be useful to have a map reference for the those two locations.
Where are you expecting this info to be?
At Worcester Bar the following info is supplied:
Latitude: 52N28'38\"
Longitude: 1W54'36\"
Postal code:B1 2HE
OS Grid:SP062865
CanalPlan:b3ft
Sunrise:5:58 AM
Sunset:8:22 PM
Date:20 August 2018
This sounds like a worthwhile idea to get put into the issue tracker, but before doing that I need to understand a bit more exactly what you mean.
I'm assuming you are talking about pages like this one: https://canalplan.org.uk/waterway/89fj
Do you mean that you'd like a label on the map to show the two ends? If so - particularly as I'm working on the maps at the moment - this should be really quite easy. If not, could you describe in more detail what you are looking for?