What to do with the answers
The ACCC's Home Loan Price Inquiry found borrowers missing out on significant savings by not switching.4 In practice the switch is often unnecessary, because the threat of it is what moves the rate.
Call your lender's retention team with three numbers: your current rate, their current advertised rate, and your loan to value ratio. Ask them to match their own offer. It is not a credit application, there is no enquiry on your file, and the downside is that they say no.
If they say no, ask what they would need to see to change the answer, and price a refinance properly before deciding. How to compare rates without being sold to covers what to look at, and how much equity you need covers whether the switch is even available to you.