I've never heard of any slang terms for "ten bob notes" either. A pound was usually a "quid" and often used in the sense of "not the full quid" for someone who was only 19/6 ("nineteen & six in the pound") ie 'not all there'. These days a similar sense is expressed as "not the sharpest knife in the drawer" or "not the brightest crayon in the box".

Australian slang was replete with terms for coins;
trey = threepence (often pronounced thruppence, rhyming with tuppence* for twopence)
zac = sixpence
deena = shilling (20 to make the full quid and 21 to make a guinea)
crown or dollar = five shillings, although neither coin has been used for yonks.

So "toadskin" in Australia would certainly refer to a paper item of currency but I doubt the usage ever applied to a 10 bob note; if it did, that usage was extremely restricted.

* hence the Australian diggers' song from WW1

I've got sixpence, jolly little sixpence,
I've got sixpence, to last me all my life.
I've got tuppence to lend
and tuppence to spend
and tuppence to send home to my wife.

Cheers, Rowan