[andrewb]

Too late to edit, but I can explain why it works through a blue bulb now.

I was under the impression that it didn't work at all with blue light, however it turns out that its just a LOT less efficient under light from the blue end of the spectrum as opposed to the light at the red end.

So if you are very close to the blue light source, it will work, but as I say you need to be closer as the solar cell is much less efficient at the blue end of the spectrum.

I think this pretty much clears everything up now.