Configuring predbat for Octopus free electricity on intelligent tarrifs

[Nilogax]

I've had an email from Octopus saying they're changing how the free electricity sessions work this year for intelligent go or intelligent flux. It seems that as long as they have control of your car/battery during the hour they will credit you with an hour's charge at off peak rates regardless of whether the connected device actually charges. Other usage remains at standard rate during the hour.

Any suggestions how to set predbat to reflect this accurately - import rates override doesn't seem viable as there may be no import and with car+solar a low import rate would usually trigger predbat to charge the house battery, but that would be at peak rate. But then if you leave Import rate at peak rate and the car charges during the hour it'd affect the cost massively..