widdly, your details will wait until either your ex does his return or until forced reconcilliation in November (from memory - they decided to hold off on retraining me until later this month for some reason lol) - at forced reconcilliation, your details will be reconciled based on the most recent estimate on file for your ex. if he later does his ITR and shows he has a lesser income than estimated, you would get a top up. i honestly can't remembe for sure

apart from carers payment and disability pension (i think) all c'link payments are taxable. you would need to do a tax return. they are paid at a level that, if they are your only income, you would not have to pay tax on them (i think - again, i'm working from memory of a couple of years ago!). the e tax system should be pretty straight forward and you'll be able to do that - if you have additional things you want to claim though (net medical expenses, child education rebates) i would consider speaking to an accountant as it's not something you want to bugger up and get a debt later.