According to AI
Yes, if you have dual citizenship, you generally need two passports (or a passport and another valid ID) because you must use the passport of the country you are entering or leaving to prove your right to be there, which means showing your home country's passport for entry/exit and your other country's passport for travel to that country. You use the passport that demonstrates your right to enter that specific country, often requiring you to carry both and use them strategically for flights and border crossings to avoid issues like denied boarding or delays
I am trying to find out how much a UK passport would cost and I don’t know the Australian $ exchange rate, but $800 sounds a lot to me.
I have just found this
Adult British passport applications by Australian residents cost from 120 pounds, plus a 19-pound courier fee, amounting to about $280.
Are these facts accurate?