it might be an earlier version of a Petty with just the rear section cut off, or if could be a european copy such as Stilmotor, M.Robert. Falk or UFO. There were and still are a couple Manufacturers who were making fenders in particular that rear one that appeared to be copies of preston pettys guards or was it the otherway around?
are there any markings under the guard?
im sure i have pictures i have printed off of that exact guard wiht those lens mounting but i would have to try and find that info i have printed off.
This is a Stilmotor A43