With all due respect to others who run a Leon ehybrid (as opposed to myself who isn't until it arrives...eventually), I can't see how 30% battery charge could come from running it in electric mode, unless the engine running as a generator & not driving the car.
Regenerating can be highly effective.
Today in the Outlander PHEV I left home with full battery and 21 miles range.
5 miles later after driving down some hills my range was 22 miles..., all from regenerating/recuperating energy from coasting downhill and some braking.
I'm over 1,000 miles this month and barely touched the fuel in the tank as lots of short town/city driving 99.9% of the time in EV mode.
I have dual rate electric tariff so charge most nights from 0 mile electric range to 20'ish miles for less than the price of a litre of petrol