The central locking on my Toyota Kluger keeps randomly activating

This sounds a lot like a problem with what's called the body computer. The unit in question controls all those functions that the car needs to have apart from the engine and transmission (which is handled by another set of computers).

When the body computer loses the plot, all sorts of havoc can ensue with the central locking, lighting, cruise-control, heating and ventilation and the entertainment systems. Interestingly, though, sometimes the body computer can be rebooted by disconnecting the battery for an hour (or overnight is even better). In some cases, this is enough to return the computer to normal function. It's a bit like the Alt-Control-Delete treatment for a personal computer that's frozen.

So see if things have improved when you reconnect the battery. If not, it's time to visit an auto electrician to sort things out.