Well after 10 gruelling months I have managed to get rid of the brumbies. The failed attempts included:
tooting the horn at them and chasing them, reasoning with them, blood and bone around the tree areas, electric fences, wire fences, cable ties on the guards pointing up, leaving bits of dead road kill around the place, extra stakes in the tree guards, firing warning shots, opening gates and just sitting near them and crying!
The successful trick was thanks to horse expert Brett Lancaster and a woman Dannika from Omeo DSE who advised leaving food in one area and then trapping them in a yard. Well I left food near an open gate and they went back to where they came from. They are still around, about 1km up our track near some old water wells. They are happy..... and I have repaired al fences and am happy too. My pine nuts are safe and I can ride freely once again.