hallo my friend  providing you have 2 good batteries making 24 volt  check your terminals on the top of batteries are tight  cos they come loose ,then you only have arelay  behind the glove box on passenger side of dash board just change that if no good there is only a sellanoid on top of starter motor and if you go across the top of the terminals and ark it out it will start ,just replace the whole startermotor for a second hand one there is only 3 bolts holding it in gearbox and 1 fat positive lead  and a little selanoid wire easy ,about 60 quid to replace . i had the same problem with my Iveco and i am not a mechanic but i know a little bit  good luck .
                 GARY PEDDER
                
 January 2018