I haven't yet..... the fault is still there. Someone mentioned a sensor under the cover of the rear view mirror, and it can be removed, cleaned and then re-fixed..... just haven't had time to have a proper look. I have the next 2 weeks off work, so as long as I can avoid the wifes "to-do-list" I might get a chance to have a look.

TBH with our recent weather, I haven't really worried about it.