Not a Catholic Hospital, and no Nuns in sight.
I don't know who picked the IMDB "Keywords" of "Catholic Hospital" and "Nuns", but neither word has anything to do with the film. Anne's title of "Sister", meant that she was a fully accredited, Graduate Nurse. Nursing Sisters were Supervisors who ran the Wards and were responsible for any number of younger nurses. Anne would have gotten her regular Nurse's Certificate, and then worked and studied for promotion.
The Nursing Veil is the British equivalent of the broad, black striped cap and full white garb that US Graduates wear.
I do hope he won't upset Henry...