I might be wrong, but I think there is a general misunderstanding, re regeneration on the Mk4 Jazz.
In my view regen occurs the moment you lift your foot off the accelerator, the car is then driving the electric motor, which becomes a generator to generate power to charge the battery.
Two degrees of regen are provided, ie 'B' & 'D' mode, with a much less degree in 'D' mode.
Use of the brake pedal provides NO additional regen braking, in fact in overall terms there is less braking energy available for regen, because that energy is then being dissipated by the friction brakes.
So, in normal driving conditions, maximum regen is provided, by lifting off the accelerator early and rolling to stop in 'B' mode, so that the footbrake is only used for the last few yards.
It's surprising how easy it is to learn this technique, which results maximum Mpg and far less brake pad wear.
My only concern is the fact that when slowing down using regen, the brakes lights are not working, which maybe of concern to a following motorist, particularly one who is already only 6ft from my rearend!!