I rejected this in the end due to the likelihood of not being able to locate it accurately in the dark. There was a certain amount of perverse logic to my final choice of swim. In the previous couple of years, I have been constantly amazed by a local friend's ability to boldly go where no modern automaton unthinking angler has gone before, as a result of which, he has fished the pants off everyone in sight. The plan was to fish on the gravel part of the upshelf, with a second rod upstream on whatever gravel I could hit in the dark. I baited up with a dropper, dividing half a gallon of hemp between each target area, and depositing a couple of droppers of WWM in the vicinity.
Confidence is a great thing when fishing and a lack of confidence is a killer.
No such thing here. In 25 years of fishing the river, no one had ever blanked in this swim to my knowledge because I had never seen anybody fish it. The state of the bank seemed to confirm the fact that certainly no one had been near it during the season. As I was to find out later, it had an interesting challenge in store. The swim contained probably the fastest water on the whole stretch, but I was able to hold bottom despite this with a 1 oz running ledger upstream on 10lb Big Game with a 12lb Merlin braid on a size 6 hook and downstream on a 1 oz ledger on similar tackle.