Partner Visa - Unpaid Tax/Debt?

Hi everyone,

I'm in the process of putting together a Partner Visa application with my Italian partner. While he was in Australia (from June 2017-June 2018) on a Working Holiday Visa, he worked briefly for Uber Eats and for two different farms.

We read on the ATO Website that if you earned all your income as a Working Holiday Maker and you earned less than $37,000 for the year, you don't have to lodge a tax return. We assumed that applied to us and didn't think anything else of it. Now coming to the visa application, we've read the question "Have you ever had a debt owed to the Australian Government?". This got us thinking about the tax return, and we've realised that we failed to take into account that Uber Eats does not withhold tax and therefore he needs to pay tax on the $5000 or so that he earned.

We're going to call the ATO to sort out any debts that need to be paid, but now we will have to answer YES to having had a debt as the deadline for lodging tax returns has passed. The debt will definitely be paid ASAP before applying for the partner visa, but can anyone advise me on whether answering YES will have a negative impact on the outcome of the visa? How can we mitigate the negative impact?

We're going to complete a statement/stat dec saying that we were confused about his tax obligation and that we have since paid the debt promptly and willingly. As the deadline was October 31, it is only a month late and is not a great amount, but we're very anxious about the implications it could have!

Any advice? Thank you!