does anyone know how the banks or valuers estimate a property market value?

Not sure how they do it. But in each state land office, you can actually purchase the list of transacted property over a period of time.

Running thru their valuation report normally I see that they establish as below.
1) surrounding comparable transacted value.
2) Investment return value.
3) Condition of the property.
4) Reconstruction cost.

They also highlight the force sales value which is way low.