Having seen a grey cone inside the pedestrian light bollard on the camp site during the day, I was interested to see how it worked.
One reason for ruling out fluorescence would be that the LEDS emit visible light. The coating on a fluorescent tube is because the light emission process in the gas produces ultraviolet that we can't see. I suspect reflection because of what you can see in the two photographs. In the first photo I must have been at the angle to which the curve is designed to reflect. Dropping down to photograph the inside meant the angle wasn't correct and it wasn't as bright.
