Thanks for that, I have a David Brown 885 here that I could 'borrow' a starter from, just to see if it fits, but that may not be the same as the starter you suggest. I could not find a plate on the Lister Petter to get any details from.You could try a starter of a DB 990 up to a 1494. Am nearly sure it will fit. (Will fit a FE 35 4 cylinder too.)
Just been out to have a look at my 885, the starter is on the left, the bolt holes seem to have the right spacing but the rotation is wrong. An associate sent me a picture of the starter numbers on his very similar twaites dumper. They are CA45F24 and Z1321F5 his is a 24 volt starter but I would think you could get the same in 12. Does this help?But the dome that covers the pinion will be in the wrong place.... Possibly fitting the starter with the solenoid at the bottom might work??
The number of the starter is in my link above along with a few cross references. Would think @ACEngineering could sort you out with a Mahle(Iskra) starter.
The number CA45F24 is for a high torque starter and is probably considerably dearer, even in 12v, than a conventional starter. The solenoid is built inside the unit. A standard type starter would be more than able to crank a 2 cylinder Petters.