Times have changed. As a child in 1960s England first names were not so common. I would never have dreamed of usung an adult's first name without a courtesy Auntie, first and at work it was a very modern thing to be on first name terms with someone senior at work. I remember there being an article about it on the news.

When we visited the US when my children were young they had to use the word Miss before an adult's first name.