Nice find Hugo, memories indeed. I am ashamed to admit I don't recall exactly where I caught my first barbel, but chances are it was one of the Thames weirs.
I do remember catching my first canoe from Hambleden weir though
At the time, my buddy and I were enjoying fishing silkweed for the roach, much like a couple of previous posters...and were being harassed by pike as we reeled them in. I decided to catch one, and set about knocking up a makeshift outfit out of what was to hand. Just as I started free lining a roach into the white water, a bunch of kayakers turned up and I very soon hooked one, my hook finding it's way into a small loop of cord hanging into the water from the pointy bit at the back of the boat. I was surprised but highly amused to find that I could turn the thing by bending into it, and it took the guy quite a while to work out what was going on
I remember too catching huge perch from Old Windsor weir. We had a traditional home made wine bottle minnow trap on a length of cord, and were legering lip-hooked minnows from that right up into the small gates at the side. Magic times. I had quite forgotten that until your thread reminded me Hugo.
Frequently, the hot spot for barbel in weir pools seemed to be the triangle of slacker water formed by the meeting of two currents, where the side flow met the main flow. The trouble was, lots of branches and other debris came to rest there too. Not a problem though, as they were invariably sworn to be record breaking barbel
Happy days.
Cheers, Dave.