Henleys - Item of Clothing for Despatch Riders?

[Grant Bowker]

Borrowed from Wiki:
A Henley shirt is a collarless pullover shirt, characterized by a round neckline and a placket about 3 to 5 inches (8 to 13 cm) long and usually having 2–5 buttons. It essentially is a collarless polo shirt. The sleeves may be either short or long, and it can be made in almost any fabric, although cotton, cotton-polyester blends, and thermals are by far the most popular. Henley shirts are generally regarded as menswear, but women's versions have appeared as business casual and casual wear as well.
Henley shirts were named because they were the traditional uniform of rowers in the English town of Henley-on-Thames.

Modern examples at:
https://www.llbean.ca/shop/Henleys/5...e=mens-henleys
for prices well below the ebay example.