No not if you remove the wing mirror and do the repairs like I explained. And of course so long as you ensure you leave the parts treated to dry for at least 24 hours (longer if you want to be sure).
Then the superglue will have dried/hardened and created a strong bond and won't do any harm whatsoever. Just don't try and glue it with the wing mirror still attached to the door, otherwise you could end up with superglue everywhere including your shiny paintwork or glass.
But like I said that's what I did for my sisters wing mirror and it was fine and dandy once the glue had dried.
Hey hang on a minute Emma, your from the Rhondda too! Well i'm living in Cwmparc now, so are you far away from me? And don't worry i'm 40 next year and not about to turn to car crime or anything, so your perfectly safe and my Mini's garaged anyway at present.