Travel Insurance Advice for UK citizens holding Australian Working Holiday Visas

For some context:

I am a uk citizen living in Australia on a working holiday visa and I’m looking to fly to the UK for a wedding in November and return to Australia afterwards, I am also taking my girlfriend with me, who is an Australian citizen. I have paid for the flights earlier this year but have only looked at getting travel insurance, in particular cancellation, luggage and whatnot.

The issue:

Because I’m not living in the uk, my trip has technically started and therefore UK insurance is refusing to cover me. I am also unable to purchase insurance in Australia as I am not an Australian citizen. I paid for the entire trip and it is in my name.

I already know that the OTA I booked the trip through will not give me a refund or credit as I have already in enquired.

Does anyone have any suggestions on methods or companies that would provide some decent travel insurance?

Edit: slight bit more context