In Cardiff our licensing authority operate a points system. Like toting up if you get to 12 points you could have your badge suspended. Things that get you points could be, abussing members of the public, abusing other taxi drivers, assaults, unfit vehicle etc. Its a fair proccess up to a point. You making a complaint after witnessing the incedent, doesn’t carry nearly as much weight as the woman making the complain. You don’t even know what was said for instance. If asked about it the driver might just say ” what woman “.
Your complaint will be noted though, and if this driver already has history it’ll have some bearing, but the council isn’t going to remove a mans livelihood on the basis of a secondhand unverified complaint.