I ended up purchasing a vintage light meter called a Weston Master Series 3. These are American made. Weston meters were made by Weston Electrical Instrument, started in the late 1800s by Edward Weston.

The Weston Master 3 were made in 1956 and was the last series to be made before the company went bust in the 1960′s. They got bought out by a British company, who continued to make them until the market for external light meters dried up. As light meters were introduced into cameras around the late 1960′s early 1970′s.
The Master III  is the first of the Masters to have the exposure index scale calibrated in ASA, not Weston, so it could still be used today without having to adjust for it (Weston EI numbers are about 1/3rd stop slower than ASA).

The light meter is in good working condition for its age and comes complete with a case and strap, however sadly it’s not for me. It’s a preset for my friend Zoe, who has a fair few vintage cameras but no light meters. But best of all I even for a Manual for it online. Saved here (Weston Master 3 Manual).