Yeah the Matilda was an awesome tank for a jungle environment, though it probably suffered from not having HE shells - not sure if they'd introduced them by 1944/45 or not. Its frontal armour was nearly as thick as a Panther's, though of course it wasn't so well sloped. But for a 26 ton tank that was pretty darn good.
The Australian Army independently developed its own HE round for the 2 Pdr. It was a base fused round, designed to penetrate the walls of earthern bunkers of the type the Japanese preferred to us. It was tested against the nose fused round developed by the British in 1943 and issued in early 1944. The Mathilda could also be armed with a 3in CS Howitzer, which fired a HE round (but no AP).