That’s why I think I am missing something in the thread, so easy to swap the complete seats on a Sprinter. Saying that the passenger seat on mine doesn’t have the IMSI(?) label that drivers seat has.
In fact Del, fit a pair of Sprinter seats, they are real comfy

Just because you can do something on a Sprinter does not mean you can just repeat it on a Ducato

I think if it were as simple as suggested, Del would have sorted it long before now.
Many (most?) seats are handed and the left and the right cannot just be swapped over without doing a fair few other things as well.
For example, you may have armrests on just one side and swapping over will put them on the wrong side. Seats may have the receiver buckle fitted on a strengthed area of the seat that is not strengthened on the opposite side, so swapping the buckles over may not be safe? there may be a moulded plastic form around the buckle and swapping the seats will means swapping those parts. Some seats have height adjustment and lumber adjustments on the drivers side only so swapping seats you will loose that for the driver. Swivels would go the wrong way if they were part of the seat if you swapped them over.
Probably other things as well to consider (here's another one ..... Side Air bags if present would be on the wrong side and face IN instead of out if you swapped the seats over).
Here's a photo of the seats I fitted to my T5 ...
T5 Seats by
David, on Flickr
Just look at the photo and you can clearly see you can't just take the seats off and swap them ... The Seat receivers, the moulding around them, the seat adjusters, the lumber adjustment, the side airbags (and maybe other things as well) all need to be dealt with.
Seats I fitted to my VW LT (Sprinter Mk1)
LT Seats by
David, on Flickr
Armrests would go to wrong side, the swivels would go in the wrong direction, the lumber support would go to the passenger. (but at least the belt receiver might be able to be moved easily?)
(FWIW, I dumped my LT Drivers Seat (which is the same as the Sprinter seat) and fitted the Seats above which are from a Ford Galaxy. Much much nicer

)