Ducato (Hobby) charging problem

mrsympathy

I have diagnosed myself that my leisure batteries are working on mains fien and my starter battery is being charged from the alternator, the lead to the leisure batteries has power at the fuse in the engine compartment but is lost en route to the leisure
batteries, does anyone know where the relay is on a fiat ducato motorhome? Before I spend a fortune on an auto electrician, is it hidden behind the dash fuses or elsewhere, van SORN so got time to find it!