It would just be a matter of running some TPS from the last light in the circuit and attaching the extra light. Nothing would need to be done at the switchboard.
It’s an IC-F rated LED downlight with HCB and SCB 0.
Simple job, but is it something a home owner is allowed to do themselves? I’d rather not have to pay a sparky a couple of hundred bucks to install a $30 light if I don’t have to.