I have just converted a LHD pair to RHD.
First file off the lugs on the mountings so that the mirror holders can be positioned at any angle.
Put them on the van and adjust the holders, with the mirror plates in the central position so that in your normal driving position the holders are set correctly.
Mark the mounting and holder with a line to show their relationship.
Take the holder and mounting apart.
Cut 6 peices off the end of a 6mm dia bar. (I used stainless steel but brass, steel will work.) Each peice needs to be about 3mm long making a small disc.
Three of these discs can now be put in the notches inside one of the mirror holders. (They are about the same size as the tops of the lugs you previously filed off.)
Put a dap of paint on the top of each of these and replace the mirror mounting into the holder with the lines you made, showing the correct relationship between holder and mounting, correctly aligned.
The paint will mark the positions on the mountings that have to be filed with a 6mm round file to accept the other half of the discs.
Carefully check how far you file down by checking the two parts together, as the mirror holders previously rested on top of the lugs. They do not sit on the flat part of the mountings. They therefore have now to sit on top of the discs. That is why there are three of them.
When a clearance fit has been acheived and the springs replaced and fully tightened, you will find your LHD mirrors will now be RHD with all the features of the LHD. Meaning they will fold in and out and lock in the correct position as before.
Incidentally, when you are using the 6mm round file to make the locations for the discs there is no need to have the file at a right angle to the mounting. Just file so that it clears the other side. (You will see what I mean when you do it!)
Reading through this it sounds a bit complicated but is dead easy to do. No need to put in ball bearings and additional springs or file bits off the back of the mirrors etc. and they look as VW whould have intended.
Keep looking backwards!