"My gallery encourages lunch break visits... very popular to relax for 15 minutes in the city... council staff use the cafe as it's the nearest real coffee to the main office...They got aggressive, began almost shouting, acted like I'd yelled at them or spoken like they were stupid or something. It was upsetting when I'd been as polite as possible to them when they knew they were openly breaking rules."
This pair were hoist by their own petard though. As they were wearing their council badges, the gallery manager was able to contact their manager about their conduct in public. This local authority apparently has rules about conduct while publicly identifiable as council staff, so having offered that tidbit, the gallery manager left the rest in the hands of their manager.