What year is your vehicle?
Before 2007 it was not that rare for the incorrect mirrors to be fitted in the Sevel Factory.
My first van, an Elddis on a Peugeot, had the wrong UK nearside mirror arms fitted. It was actually a Drivers mirror for a LHD vehicle. I had to take the van back to the Garage that did the original vehicle PDI checks and get them to sort it out (a round trip of nearly 200 miles)
A later van of mine, a Burstner 747, had the wrong mirror arms on the UK drivers side. I could adjust the mirror enough to get a reasonable view so I just left it at that.
You might be surprised at how many mirror arm variants there are available. 8-)