Some folks are great casters not all of those can teach well .
I did a Falkus 5 day speycasting course many years ago ,had a great time met a few folk I still talk to some 30 years later ,yes I was about able to do the standard cast ,but hey 5 days !
Mick Bloke Bell had my son casting the single...
Re the Chess rainbows ,I had a rod on the stretch below Latimer Park for 3 /4 years back in early 80s
We caught a few but mainly browns .
they did seem different to the derbyshire ones and didnt reach large sizes frow what I saw .
the last year I had a rod the river started to smell of sewerage...