A lot of helpful information there guys, and lots of options to look through-much appreciated.
With hindsight, I probabaly should have phrased the initial post differently, or at least been clearer.
I have two small identical RSPZ lights. (see photos). The lense area is just 25mm dia, and they are each powered by 4x AAA 1.5v batteries. There is just one LED (about 3mm dia) in the center of the light. They were bought with the single intention of road cycling which they are very good for-one in steady mode & the other in flashing mode. I always use them in this mode on the road, even in the daytime-I want to be seen by vehicles waiting to pull out, or oncoming vehicles wanting to turn right (in front of me).
Although I am easily seen on the canal day or night, they are not good enough to light the route in front of me at night.
I acknowledge that what I originally enquired about is akin to driving a car with full beam on constantly , along a country lane towards other road uses.
I simply want and need to be able to see the canal route ahead, inluding pot holes/uneven areas, debris and tree branches etc. I would be cycling at no more than 20mph, (12mph to 15mp most of the time).
If I am doing the canal run all within the day time, I won't need to have the "canal light" with me. So one with a quick release method would be ideal.