took a bit of figuring out this one, dad got it in the end

this is what we think

Thats what the mounting bracket is on the back, and also the accelerator lever :p its also why the back door and triangle are missing.
the thing on on the steering wheel is for locking the steering out, so that the mog can be moved forward without having to get off the digger and in the cab. if this is the case its a high chance that it has hydrostatic drive, very nice

did he get any pics of the gear levers?