you could be paying too much.
From the Flat Rock Creek car park (West of Flat Rock Creek bridge, 6.6KM south of Audley on Sir Bertram Stevens Dr), this walk follows the track past the 'Flat Rock Creek' sign. Following the arrow down the rock the walk then winds through the bush passing some interesting rock formations and views of the creek. Just near the creek the track heads right to come to the bank of Flat Rock Creek. (The creek may be impassable after rain, and is slippery).
A list of the nearest UHF CB repeaters I found to Flat Rock Creek.