I had painted the gunners earlier, but I had forgot about the gun. It's an Italian Deport 75mm as developed by the French Colonel Deport just before WW1 and then used through into WW2, with numbers used then being captured in North Africa.
It had a novel recoil system and was also the first gun with a split trail. More details on the Landships site. My model came from Rolf Hedges, but HaT have also shown roughs of their proposed model on their forum.