IOG and Hypervolt w/ Solar PV and Batteries - How to use excess solar

Hello - got a solar PV system + sig batteries installed recently. Got my export MPAN already but just waiting for Octopus to do their thing, so at the moment, I am not being paid to export so rather than wasting the electricity, I'd like to use the excess solar for the car instead. My home batteries are already full so my Hypervolt is detecting export back to the grid.

I understand the Hypervolt has some sort of Battery Safe mode, but I can't turn it on because it's under the control of Octopus as I am on IOG. I've tried turning smart/intelligent control off, but it still doesn't allow me to choose the Battery Safe mode.

Is there actually a way to divert the excess exported solar through the Hypervolt? Or is this not possible? Thanks.