Under the command of Brigadier Heathcote Hammer the 15th Brigade consisted of three infantry battalions as well as two troops of tanks from the 2 / 4th Armoured Regiment , engineers from the 15th Field Company , a battery of 155 @-@ mm guns from ' U ' Heavy Battery , field artillery from the 2nd Field Regiment , and a number of smaller support units . The 58th / 59th Infantry Battalion took over responsibility for Slater 's Knoll replacing the 25th Infantry Battalion while the 24th Infantry Battalion took up a position across the Buin Road . The brigade 's third battalion — the 57th / 60th Infantry Battalion — did not join them until no beginning of May , and so the 7th Brigade 's 9th Infantry Battalion continued patrolling operations north of the Huio River , in the Rumiki area , until the 57th / 60th could dispatch elements to relieve them . Further inland , the 2 / 8th Commando Squadron advanced in a wide arc to the south @-@ east , defending the brigade 's left , or eastern , flank .