Tax resident nowhere

I am a UK citizen, but I have been living and working abroad since 2013. I have not met the Statutory Residency Tests for UK since 2013. I do not have any UK-based income, or property. I have now moved to Australia, on a Working Holiday (subclass 417) visa. I have contacted the Australian Tax Office and they have confirmed in a private ruling that they do NOT deem me Australian resident for tax purposes. This would seem to indicate that I am not tax resident anywhere. I have a few problems with this: 1) I am not able to successfully fill out many applications at financial institutions as they require you to be tax resident somewhere. 2) If in future I have non-Australian income (for example capital gains on US stocks) I do not know where to report that income. Can you offer any advice about how to resolve this situation or point me to past precedent? I want to be compliant. The most important aspect for me is to understand what obligations I have to HMRC.

Hi Owen,
An individual may also be resident in the UK if they are here for fewer than 183 days in a tax year.
This will depend on how often and how long they are here, the purpose and pattern of their visits and their connections to the UK.
This might include the location of their family, their property, their work life and social connections.
If the nature and degree of ties to the UK show that it is usual for an individual to live in the UK, they are resident in the UK.
Thank you.