You can't claim online, but you can phone them - that is how I have done mine and you get the refund in 14 days. You need to download and print the form and fill it all in and have it in front of you when you call. You can only claim things that relate directly to the education of the child, so uniforms etc aren't included because they aren't directly related to education.
If you post it to ato, u have to include receipts for proof right?

If you phone them, how do they check your claims are true?