You can run any diesel engine on cooking oil, however some of the problems are as follows:
Some fuel pumps die pretty quick as they need the lubrication from the diesel.
Cold starting can be a nightmare on 100% veg oil
It is recomended to heat the veg oil before it enters the engine - loads of kits out there for this.
Veg oil can solidify within the engine and fuel lines etc which will obviously cause issues.
I ran my C15 on 100% veg oil with the only problem occuring when trying to start it in the mornings. (took about 25 seconds of starter motor to get things going) which killed the starter after about 6 months.
My dads series 3 landrover is running 50% veg oil with no modifications.
I haven't tried my scudo on veg oil yet, I've got the 1.9td if I did I'd try a small mix 75% diesel 25% veg oil, see how it goes sort of thing.