Bike fit / correct riding position

That method was popular into the 1960s but long discredited. Goniometer models are, however, a close relative that appears to produce OK positions.

Yeah those cunts at British Cycling are pure wastemen

You shouldn't be able to touch the floor with both feet when sitting on the saddle! An all too common myth and a hangover from your learner days. To set your saddle height correctly, sit on the bike and rotate the pedals until one of them is at the furthermost position from the saddle (i.e. in line with the seat tube). Your leg should be very slightly bent and you should be able to turn the pedals without stretching, pointing your toe or rocking your hips.