When I owned my “Banbury Run Bike” a 1928 AJS K9, a 500cc side valve single, it was a remarkably smooth running motorcycle, considering how ancient it was, that had the headlamp mounted on the bottom of the steering headstock, very similar to the FF33 mounting, and used 2 bent round metal rods threaded at the fork end for attachment to the headstock, and plain at the headlamp end for the headlamp to clamp onto. Most of the time it was fine, but when ticking over the headlamp would vibrate excessively, so much so it snapped the support at the forks end, and required a welded repair.