EBBCO / East Berkshire Boat Company

[_Firebird_]

I've acquired an old EBBCO Plastic Sextant and wondered about their history - I can see the company name was the East Berkshire Boat Company, based on the Wargrave Road near Henley-on-Thames, and the sextant is stamped as having been made by Henley Plastics Ltd but can't find much else out about them.

I was curious as I grew up near Henley, and can't really see many river users needing a sextant! Does anyone know anything about how they came to make sextants?