commercial work is busy in NSW, Vic and Q'land, mostly K Stage work, they generally will take working holiday visas
industrial construction is winding down in WA, Q'land and NT, they dont like WH visas
there is always scaffoldingwork in Australia, ive been here nearly 30 yrs, its a good place but thers a big difference between scaffolding in the UK and here.It will take you a long time to adapt to the way things are done here, but generally UK trained guys do well.
be minfull the cost of living is high, google rents, price of beer and all the other core values in life. good luck