I wouldn’t assume anything in these matters some DNOs are better than others. As long as the charger was rated appropriately everyone was happy to install on a 60A cutout here and in fact with a looped supply too, that could well be why it’s been setup this way here.
Time to check paperwork and see if the DNO did upgrade the fuse or not. When was this installed if it’s been like this with ct not reading then get the installer back
