The Landships article has a drawing of the lMW n.A:
The trail and wheels could be removed and the mortar fired from the baseplate - this was most often the configuration in defensive positions.
There were a couple of late war modifications for low angle fire. One of these modified the shape of the trail so the residual recoil forces could be absorbed more
effectively. There's a survivor at Irvinebank, Qld http://www.ammsbrisbane.com/documentation/lmw_11.html
). The other is quite rare and seemed to
have had a cut down baseplate - sorry no images of this one.
There are a fair number of surviving lMWs in Qld -http://www.ammsbrisbane.com/documentation.htm.