@DattoFrog
I did have a good look online, but came up with absolutely nothing for brake shoes. I ended up going to a brake place in Morth Melbourne that I've been to some years ago. I presented my dirty shoes and drums and told the lady on the counter it was Datsun Stanza whereupon she consulted a computer and a couple of very dog eared and greasy finger marked catalogues and identified two possibilities - both for a stanza. One (I guess) would be for the (import) H165 axle and brakes and the other the BW axle and (girlock) brakes. She matched one of the diagrams of the shoe shape to my shoes and went off up the back to see what she could find.

Then one of the guys working there came in from outside and walked over to the counter and had a look. "Datsun 1384" he says (the catalogue number for the shoes). "Don't have em in stock, but can fix yours. Not so common these days!"
He proceeded to tell me that he seriously considered putting himself up for the old TV show "Mastermind" special topic: brake shoes!

@Datsandy @ddgonzal:
I checked the backing plate and there's no hole that gives access to the adjuster. Also no hole in the drum to access it from the other direction. I'm sure Mr Mastermind will have the answer.