Well under £10 in Oct, Nov, Dec according to the Ohme app. No public charging was required in those months.
But it's misleading, because my wife gets free charging at work (how long this will last, we'll just have to see).
Our home charging is 7p/kWh because I'm on Intelligent Octopus, but that doesn't tell the whole story because there's a standing charge, and daytime electricity is a bit more expensive than other tariffs. I do suspect that with our low utilisation of the charger, it might be cheaper overall to not be on Intelligent -- but it's so cool! And I do run the dishwasher on the cheap rate...
GiffGaff (phone service) send you a monthly report, including advising you which of their tariffs would have been cheaper for you based on the previous month's usage. It would be nice to get similar from Octopus.