It almost certainly wasn't 'sexism', it was simply that there was an 'internal candidate' who the interview board knew and liked, so they were (very, and unreasonably) heavily biased against the unknown outside candidate. Had she travelled 20 miles and had expenses reimbursed it'd be a non-story, the panel - if they'd had any brains - should have come up with some questions that the internal candidate would have been likely to answer better, then religiously recorded what was said - end of complaint, they could claim that 'surprisingly' Mr X interviewed better so got the job.
It happens - I've been on a panel that selected a surprisingly good outsider against a well known and liked internal candidate, and whilst convinced the right candidate was selected I still felt like a complete s**t for doing so.