Photographed these two mortars on guard at an ex-servicemans club in Tasmania, Australia last week.
They appear to be 25cm versions. The one on the left is marked 6387 & the right one is 552. Apart from the muzzel shapes they are identical.
I also found a restored 1918 horse-drawn Army supply-wagon.
They are in Deloraine, Tas. They are both 17cm mittlerer Minenwerfer. The one on the right is an a.A (alte Art) and the other is an n.A (neuer Art) with a longer barrel.
Regards,
Charlie