Wireless remote control unit A, serial no.4869, for wireless set No.11

[Danger]

Hey guys,

This old 1941 Wireless remote control unit A, had been sitting in a shed and was going to get chucked out.
The previous owner had passed away and the family were doing a clean up.
He had been in WW2, they didn't say what or where.
They were keeping his medals and uniform as you would expect, but they didn't want the dirty old box of knobs.
So it cost me $5 to stop them from smashing it up, and now it's safe.
It needs a hell of a clean up, but some parts are long done for. Bloody shame.
Best I can do is preserve what's left of it.

Can anyone please tell me what it was used for? Part of a bigger set up?
Or a small carry around unit?
Is it a rare unit or common enough?
The only other picture of one I can find is in a museum in Aussie.

K409-4/3 Wireless remote control unit A, serial no.16551, for wireless set No.11 - Powerhouse Museum Collection

Thanks

[Danger]

Made in Aussie right?
How many were made?

[Danger]

Bump