Thanks Folks I got all them working now.
But having tried the lights hammocking in the woods last night I realised it would have to be an odd occasion I needed to use it at half power. On the normal lowest setting, I can only read my watch with the light a few inches away.
This really is a terrific light though! from the feeblest illuminaton to more powerful than a mini maglite, so good for all occassions. The gimmicky looking clip works very well. Grips like an alligator on anything (you don't need a cap with a visor -I wear a watch cap, but shirt, jacket, anything works.) and can adjust to any angle. All my other lights just got relegated to cupboard ware.
One definitely needs the 'bulb' tube; without it, using it as a headlamp would be like working with a light shining in your eyes from a few inches.
With friends like me pointing out Photon now sell them and marantz telling you how to make your own; Doug doesn't need enemies :-). But Dougs is still better. Try finding a black light on the forest floor at night if it falls nose down in the dirt.
By the way; just got the DD Hammock and will never camp on the ground anywhere with trees again. Luxury! tip; I put my ridgerest mat (gave up on the inflatables; they always leak on me) inside the sleeping bag so can be sure I'm lying on it. Otherwise I keep finding half of it is out of the hammock.
qjs