Let’s say you actually do the exact 20-80 charge, that’s 60kWh or 77% of the available battery. So multiply the 60 by the price and if you choose the wrong charger you’ll be around the £45.
Charging at home is significantly cheaper. Octopus can go really low, even paying you to charge if demand is low enough. If you charge as low as 5p per kW, you’ll pay £3 for that charge.
Most EV drivers look at the price per mile, which reflects efficiency of the car and cost effectiveness of the power purchased. In this case, assuming a warm rate of 4.5 miles per kWh that’s 1p per mile home charged, 16p per mile at 75p per kWh.
I'm Autistic, if I say something you find offensive, please let me know, I can guarantee it was unintentional.
I'll try to give my honest opinion but am always open to learning.
Mark