Ann: Half year financial results, page-79

Booking impairments/adjustments that, normally, would be written off over a longer period of time, is usually to get rid of the bad news in one swoop.......means that future progress, earnings, accurately reflect ongoing operations, and are not reduced to reflect the past, sometimes long past, challenges.
As to the absence of, for example, monthly production figures, which I'd love to see, can think of a few reasons. The most cynical, and not really my 'go to', is that insiders are forbidden from trading during certain periods, limiting them to trade between quarterly's as it were ( not sure your Aussi rules same as ours ).
Or, maybe a, leave us alone to get our work done.....we don't want to need to explain every bump in the road, every minor variance in production.
Or could be a matter of trust.....as in, if you don't think I/we are worthy of your trust, then please, invest somewhere else. Those who trust us, welcome aboard.