The standard wing mirrors as supplied by the factory are pretty awful. Vibration and the small field-of-view from the flat glass render them basically useless. Back when I got the car one of the first things I did was to improve the standard mirrors. I got new convex glass which I glued on top of the existing glass, and then filled the base units with glue to reduce the movement and vibration of the unit. This helped a lot and gave me wing mirrors that actual function properly !
With the weather improving I've been doing short drives in the car with the side screens removed. It's a slightly different experience, and I like it for little blats. So today I got a small wing mirror from Demon Tweaks that I can attach to the windscreen to improve the rear view when the side screens are off.
This attaches to the windscreen stanchion with 2 grub screws that press down on a plate. I'm just testing one on the driver's side, if it works well I may get another for the off-side. For £38 I think this is a great little mirror for a chrome-finish car.