@StarFleet Carl
Is he the real deal or just a fraud? The slang book used clanger as 'telling a really big lie'. It mentions 'Claytons' as a fake. King pin, of course, is used in mob terms as a big shot.
While I've only visited Western Australia a few times on holidays and lived my life on the east coast, with most of it in NSW, I can truthfully say I've never heard anyone use the word clanger to mean a big lie, but I have heard it used to mean some action or activity was a big mistake. Although I'm more used to hearing people say something came a cropper than was a clanger.
Never heard king pin used to mean someone important until the late 20th century due to it being picked up from the US movies and books. The leader of criminal gangs was usually referred to by their name, nickname, or simply the boss.
Claytons is used as slang for fake or faux, but this only started in the 1970s following an advertising campaign stating the non-alcoholic Claytons was the drink to have when you're not having a drink. It coincided with a major campaign against drink driving by having a designated driver. Thus the designated driver could have a soft drink that looked like he was drinking whiskey by drinking Claytons and dry etc.
As to being a pregnant and living on welfare, never heard any of that. Someone living on welfare when they're fit enough to actually work but aren't looking for a job is called a dole bludger. There are many regional terms for a single mother who makes a living by frequently getting pregnant by different men, and the nicest I've heard was a professional breeder.
If the use of the terms you mention came from a single source, I would regard the source as extremely suspect.
There are lots of Australian books, movies, and TV shows you can use for sources of Aussie slang. However, I'd concentrate on anything from before 1990 for the more accurate works. While some of the movies are very jingoistic like the Crocodile Dundee series most are fairly accurate with the use of slang and daily language. The series Anzacs, The Sullivans, Return to Eden, Cop Shop, Homicide, Blue Heelers, All Saints, The Flying Doctors, McLeod's Daughters, Spy Force, and Bell Bird are good options, so are any movies with Chips Rafferty in them.