(Now what WAS screwed up way-early were Indian (US) controls), including a backwards twist-grip!
that is: you 'closed the throttle' by turning hand CCW==towards-you! ... counter-intutive-you-bet.)

Maybe he meant (more likely) that shifting is via right foot. and rear-brake is on the left. The Japanese thought ever-so-"logic"-ally that:
both brakes (hand & foot) should be on same side, thus shifting was moved to left-side as they entered the world cycle markets.
Because Honda (+ Kawa) aced most other world mfgs' outputs by end of '60s--this became Std. And Bad:

[Under: Nothing is ever Simple]
What the Brits had Right (sans any 'kinesiology' tests of those days) was a phenom I mentioned here, once:
Seems that the brain handles more speedily the cross-wise pairing of RH + LF for braking (something which needs front-to-rear precisely-coordinated braking force)
The gear-changing side is immaterial per se, but obv. must be on right: for left foot braking.
This has to do, apparently with the brain-wiring at the nexus where motor-decisions are made and that network introduces a certain delay IF:
a right foot AND a right hand are given similar tasks (!)

Some boffins measured reaction times of the two conventions and the Brit. original--as on Vincent--was measurably quicker to respond to brain-commands.
Who'd a THUNK! eh?

(I know I Hated-it when I got my first Honda, a 305 cc twin; it felt-Wrong, not because I knew what these boffins deduced much later:
but I experienced the ..lag in accommodating smooth 'commands' (though never suspected.. there was a Right/Wrong way! to place braking controls.)

TMI to detail, but re Reserve gas: you had a tap on both sides of tank: either one could feed both carbs But it was recommended, for high speeds
--that both be opened. If he opened only one? He had a reserve on other side (one side 'saved' more petrol, however, etc.)

So given his other cycle experience--sounds as if he hopped on the Vincent from ... many Japanese-mode bikes, had no familiarity ride before beginning this 'race' etc.
Not reading brief manual re Reserve options. Sloppy form there.

(But these details pale into insignificance with today's transistorized factory-racers and beyond-human power-on-tap.)
After all, this was just a soap opera production, not the I.O.M.