one of the DUMBEST things Daimler Benz did was to export thousands of lowly 115 chassis cars to America with only one mirror, on the Drivers (LHD) side. I thought that an image of a car built to high standards and without a simple safety thing like side mounted mirror was pretty cheap!
The late version 115 is what was pictured previously, with the inside adjustment lever, and they can be hard to find. It seem like anytime one goes looking for 114/115 parts they seem to get scarce but when you don't need one they show up. I bought a unused old stock heater valve from a Brit a few years ago on eBay, it was a sleeper, cost me all of $30 including shipping, and was a beautiful all brass valve still in the box I believe Its now resting in my spares inventory.
There were Shopforum members in Australia scouting for the exact same mirrors you are looking for, they were going to sell them over here but I think nothing ever transpired.
I never found one for my car and its now gone to MB heaven. Now I have a car with the triangular mirrors on it, same story, none delivered on the right side!
Good luck in your search! I believe you will be more likely to find one in the UK than over here.