I have just spotted a u-tube video of the Kittoe and Brotherhood beam engine at Coldharbour Mill in Devon, which looks very much like the Stothert and Pitt engine I am building as a model - and is similar vintage. The Stothert and Pitt engine (still tucked away at Bath Uni) has the governor in the same place, but it is a bit of a mystery as there is no sign that it ever operated anything (two helpful people have examined it and photographed it). The Coldharbour engine has a seemingly identical governor in the same place - so if anyone knows about this engine or has a photo of it, then I am curious to learn if the governor does anything or not.
Steve