It may be this according to wikipedia in the bottom details, I don't know if that ties with your log book V5c details? Maybe brouse Fiat Ducato in wikipedia search and see what you think
Failing that this version
View attachment 431217 which I would have thought more popular as a PSA Group engine used in many Peugeots etc. 1.9 L
PSA XUD9 turbo I4
I just put your Reg. in a GSF parts supplier and got this, is it one your garage tried, it is an LUK make? Also on eBay if an XUD9 engine there are several clutches advertised.