I've worked in the private sector, the voluntary sector and now public sector. For an uncompromising attitude to timekeeping, public sector was far stricter than the others. Private sector was small businesses, if we had a slow day then we would be told we could leave half an hour early. Could pop out to the shops for 10 mins occasionally. We would stay late if required, 20 mins unpaid, for eg. Just more flexibility. Voluntary sector I worked in, I loved the job & did my hours, but others didn't & no-one bothered. In my current job there's never a slow afternoon, and even if I needed to pop to the chemist for tampons or paracetemol, I would have to get permission from my line manager & check back in with them on return & tI would take the time out of my lunchbreak probably. Working from home the apps I work on will show managers exactly what work I've done, with times.Hospital appointments we have to make up the time for (except antenatal which is a statutory right). I think this is fair enough, but I dislike the "public sector skivers" myth for obvious reasons.
If a manager was being paid for 6 hours a week they hadn't worked, and this had been happening for over a year, I personally would have to say something. If someone was taking £100 a week out of the till, you would probably feel you had to speak out - it's the same thing! Via Union reps or "speaking out" reps is a really good suggestion.If there is an explanation, your team could be given this in general terms without divulging any confidential information but as this hasn't been done, no wonder you assume it's unauthorised absence.