When I worked in the NHS, for a while and a long time ago, the system seemed very clear: SRN - blue stripes, SEN - green stripes, acilliary, cleaners, etc., something else, often white or pink. More senior nurses were usually solid blue.The important sentence in the above is:
This confuses patients, who often assume that everyone is a nurse.
That is the intention. They want the hospital to look well staffed with nurses, but not spend any money. It’s an illusion. They did it with the police, PCSOs uniform being very similar to a police officer’s.
Trouble was, even then, not all hospitals (or areas or regions) had the same system. There were still some that had "fancy" headgear and other local divergences.