The most my wallbox has fed my 450h (0 EV miles) is 14.28kwh which took 2h 26m. A couple of things to note: 1. There is some inevitable loss of energy from the wallbox to the vehicle so the car battery will have received a few % points less than 14.28 kWh. 2. The wallbox charges at maximum kWh for around 2 hours then slowly throttles back as the on board car charger tapers the input kWh down to zero.
BTW Intelligent Octopus Go has a cheap rate of 7.5p/kWh and as you already have a Ohme box, which is supported, you should look at that option which is not the same as agile Octopus and has specific daytime and overnight (23.30 - 05.30) rates.