Hello Robbie, and welcome (back) to REMLR.
You have probably already guessed as to the radio fitment by your user ID, Larkspur. As you have 161Bty tac signs, the typical fitment by Artillery units was the B48 Larkspur, although NZ Army also made wide use of the C11/R210.
And good to see a little bit of Lithgow on your vehicle.