Valuations on Deceased Estate acreage???

Hello all, My question today relates to a deceased estate that belongs to my late father.

I wish to approach real estate agents in the local area to the farm (it's rural QLD), with a view to obtaining
indicative values on each of the lots/titles that are in the property. Let me explain some circumstances first… I have had to lodge a claim against the estate by way of the Succession Act within the QLD courts.
One other person has executor rights and has not provided the estimated value of these lots.
My need is to obtain these valuations to present in court to support my claim.

What is the best way to approach 3 seperate real estates and tell them my story, and gain 3 different valuations on these lots of land. I have all the details of the land ie; lot numbers and title numbers ect.

All I need is a dollar value at the end of the day, so will this be easy enough to get?
Does it cost anything to get this information?

I am looking at getting the 3 separate valuations in the same day, that should be possible right? ( One town, 15 real estate agents in it).

Thanks so much in regards to any accurate info anyone can offer, much appreciated.
Mork