I was able to get the 4euro 51 cents support piece from the dealership today and it looks like it might fit. I don't know for sure just yet as there are some subtle differences.
1242670140 is on the left (my original now NLA part) and 2022670161 is on the right (the new surprisingly cheap for Mercedes bit)
I should be able to assemble it and check to see if it works later on this week (with any luck).