Hello,
I shared this picture of a mystery siren a while ago on another forum, however it was never confirmed to be a specific make/model.
It has been suggested that it could be a 2 HP Castle Castings siren or potentially an early Secomak GP6, however a conclusion was never reached.
This siren is located on the East of England Showgrounds in Peterborough on one of the office buildings, I believe.
It can be seen on Google Maps here --> https://www.google.com/maps/@52.544657, ... 192!8i4096