No reason that you can't weld repair it, depends on how good you are with the mig, to be honest I would have thought mig was a bit of a blunt instrument for such a small repair, TIG would probably suit that application better, might be an idea to take it to a professional , my local TIG welder would charge less than a tenner for a small job like that, all depends on what kit you have and your level of skill/experience.
