Say you ditch the ZS because electricity is too dear, how do you feel about domestic use?
Install a domestic battery to cover your daily use and switch to Octopus Go, pay 7 times less. And buy the ZS, and charge it at the cheap off peak rate.
If Octopus goes bust the only way to protect your investment is to have solar panels installed as well to make use of the batteries.
Alternatively if you don't want/cannot install a battery do what others suggested already and switch to Octopus Go anyway, 7.5p/kwh for the EV.