Take a standard mirror glass
And the LED (Light Emitting Diode)'s from ebay
You will note the LED's are slightly too big so they need to be carefully trimmed, taking care not to damage the electrical tracks, a nail file is ideal.
Trim, and mark around the LED's, Note the clips to hold the mirror to the motors are not to be cut off!!
There are two ways to proceed. i shall deal with them one at a time.
Stick the whole mirror assy in a pan and boil for 5 mins. remove the mirror assy from the pan and carefully with a flat blade remove the mirror from the plastic housing
Clean the back of the mirror ( i used white spirit) You may need to reboil the plastic casing again to remove the heater element
You can then either cut the end of the heater element and cut the leds into the plastic back on its own
Or you can leave it in situ and cut both together.
Replace the mirror glass with a thin film of good quality silicone. Turn the mirror assy over and seal with black silicone.
All done from the back, less invasive but fiddly
Trim and mark the LED as before and using a hot stanley knife continually score the black plastic whilst re heating the stanley blade
Once you have reached the heater element gently heat the section to be removed with a blowlamp or gas iron, remove, cut around the edge of the heater element and remove. this will leave you looking at the back of the mirror. clean with white spirit
Fit the LED's
Cover in black silicone as previously shown.
Wiring is taken from the front wing indicator. I have installed the wiring alongside the original through the mirror
I managed to get the wires inside the original convoluted tubing between the door and the car body and on to the wing indicator.
Hope this helps anyone who fancies a go