Hi Stephen, the company has been in existence since the end of the 19th Century, I think 1898, and has changed name and location once or twice over the years. It has also ventured into other areas of business, whether within the same company or as separate entities I’m not sure. I do know they they used to produce small steam engines and boilers for small boats so I am certain that the one you remember will also have been one of theirs.
As an example of their diversity Stuart Turner produced an engine for the Dayton motorcycle in 1910, followed by their own shaft-driven motorcycle. This was followed by a successful range of portable electrical power generators (installed on Ernest Shackleton’s polar expedition ship). The 1930s saw the introduction of a successful range of outboard boat engines, lightweight “back-packable” S.T. generators being used by two teams trying to conquer Everest, and the development of techniques for pump technology. With this range of new enterprises on the horizon, the model engineering business was separated out as Stuart Models in around 1930.
Stuart Turner still exist today whose main business is now water pump technology (used in products such as power showers). A totally separate company although from the same roots, Stuart Models, now located in Bridport, Dorset still produce a range of steam models, many of which are produced from the same designs introduced over 100 years ago.