//public services body is located in an area of the country with a certain mix of people from different economic backgrounds, and the survey finds that everyone working for that department are Oxbridge graduates, it may highlight an otherwise undetected issue with the recruitment process.//
It may do, and it may not, SP. In your extreme case (100% Oxbridge) I might find myself curious. But what if it were 20% Oxbridge? Or 75% female? Why would either of those necessarily matter? I do not agonise how poorly represented white athletes are in the GB track and field events. Why should I unless there were some prior indication that white athletes are being discriminated against? And before I set out on a witch-hunt to root out and persecute the discriminators and establish "balance" I would need better indications of bias than the complaints of a few white sprinters who didn't make the team. I don't think you would disagree with me in THIS case, would you?