Hi & welcome to the forums someone will know the answer to your question im sure!
I have no idea! but my guess would be how many weeks the rustproofing was likely to last! bhp is 127 i think!.
joking aside if serviced well they have a good reputation for keeping on going- generally its the body work that suffers most. along with some cheep interior fittings! sure you will enjoy it overall!
Are you sure it’s a Lwb and not a MWB as the medium wheel base comes up if you look for the Ducato 18 JTD and the 5.4metre long medium wheel base just happens to be 18 feet…. Ducato 18 = 18 feet long… how long is your van nose to tail