I actually went ahead and pluged in 2 of the large plugs and surprisingly the keyless entry module worked. That is, the key locks and unlocks the doors using the buttons!
But...... there are 2 plugs (2 wires in total together) which aren't connected to anything:
the blue with red stripe wire - via the wire tap (didn't tap it in as I don't know where to)
the brown wire - I thought plugged into keyhole illumination like the footwell lights but it doesnt fit
I'm still unsure where these 2 go into. I suspect 2. does not work as my car is the facelift model whereas the jumper loom may be for pre-facelift (?)
Anyone got any ideas?
You're right, keyless is different in today's world but that's probably because the definition evolved over the years. It's named as keyless in the official accessories brochure by Toyota.
What this box does is basically what you described; remote central locking/unlocking without using the physical key.