Straight from ATO website -

Q30: Is there any need for apportionment of computer and internet costs if they are not used exclusively for educational purposes?
For the purposes of claiming the Education Tax Refund, no apportionment of costs is necessary



Nic - Do you claim the FTB for your kids, or is it in hubby's name. The ETR must be claimed by the person who receives the FTB, maybe that's why your hubby can't claim it?