No worries. It's probably easier for you to source them in Melbourne.
I think you'll struggle for a trade. Front brakes are not the done thing in BMX... racers have never used them and I haven't seen front brakes (U-brakes or V-brakes) on a freestyle bike for years... you only get the little bulldog calipers sold on new complete bikes to satisfy the law. I assume the forks you have are from a late 90's bike, maybe early 00's.
And as long as the forks have a 1 1/8" steerer tube they will fit. It's
the standard for BMX. And it's not like road or mountainbikes... BMX stuff is all easily interchangable, there aren't 15 different standards going on. 1" forks disappeared at least ten years ago.
You'll probably have more luck on
ebay or gumtree though - I don't see many people on here talking about BMX bikes.