Trefor and to a lesser extent Tony Miles did much of their fishing around the time that their books came out on the Bristol Avon. The stock on that river now is probably 5 or (at best) 10 % of what it was in the early ‘90’s.
I was fishing there then and met Trefor on numerous occasions; 2 of my (then) close fishing mates fished with him on a regular basis.
One of those mates came up with a static fishing method that was so effective that Trefor memorably described it as ‘cheating’. We reckoned that it was 3x more effective than old style roving.
Obviously on a 2024, low stock river those statistics are irrelevant, but for what it is worth my current fishing mate and I tend to rove when we are ‘learning’ stretches and then only fish short sessions in the best spots in the best conditions, Many of my trips are less than 2 hours duration and usually only involve 1 or at most 2 swims. But it has to be said that many are blanks.
I’ve no idea whether staying there for 6 hours would have generated a bite; I somewhat doubt it…….