EV "Prevent Battery Discharging to EV" doesnt work

I have a givenergy inverter and 2 batteries that were all working fine in the app. I got a Givenergy EV charger fitted about 3 months later. My set up is to have the battery and car charge between 2 and 5am at the cheap rate so the car is full and the battery has a charge built up.
Yesterday for the first time I went to charge the car up and noticed that when I put it on a fast grid charge the battery was getting drained at 3.6kw to charge the car (remaining 3.4kw coming from the grid/solar).
I specifically set the option in the EV settings on the app to not discarge the battery to the car but it is doing it anyway.
My installer (yesterday) said to put the battery discharge wattage to 0w to stop this but when this was done the battery wouldnt discharge at all, not just when the EV was charging, so I basically was using no battery all day. I shouldnt have to go into the battery options every time I put the car onto charge surely?
Why is the "Prevent Battery Discharging to EV" option not working? I read somewhere about the CT clamps needing to be positioned correctly for the inverter and battery to identify when the car is charging, is this maybe done incorrectly.
Also between 2 and 5am will the battery ONLY allow itself to charge or will it also discharge at the same time with the car being set to charge at that time too, would make the whole thing pointless?
Pulling my hair out!!

webby how is the EVC connected? Is it connected into the same consumer unit as the inverter or is it connected before the consumer unit at the meter?

Hi matt,
I've just had tondraw myself a schematic to figure it out.
The solar panels and battery connect to the inverter which then is cabled into the house to a fuse box for the solar connections, this then feeds to the house meter and domestic fuse board. The EV charger comes straight from the wall charging point into the solar fuse box and doesn't connect directly to the inverter.
Last night it did charge both the battery and EV at 2 to 5 am without issue, it's just if I try and force a charge during the day it uses battery and grid even when i have the battery discharge set to zero for EV charging.

So I'm thinking when the EV is set to charge it just looks like the power is drawing from the house as it doesn't have a separate connection to distinguish the EV and domestic load. I take it the EV charger should come direct from the inverter so.it knows its the EV supplying and not the house.