Ducato van has a big fan.
BUT, I rang Kenlowe and spoke to their applications engineer. He advised me NOT to swap the Viscous for electric. Aviscous fan will shift twice as much air as a pair of 12" HD fans (you can't fit 2 13" IIRC) but basically the biggest fans they sell that fit will not do the job as well as a sorted vsicous.
So I bought a new viscous and rad, my car has been sorted since, well cooling wise anyway.