I use a deal extreme block for my helmet, (just like the lock blocks) and they never move. Excellent. If they move on the handlebars, I would just recommend putting some grip tape around the bar first, but I guarantee the torch won't move in the block.
Also.. they replied about the circuit board saying they couldn't get a replacement so I have to send the whole thing back for RMA. I have asked if that is the whole lot (Light + battery + head mount etc) but they have not responded yet. However, here's the good bit.. It's a UK (yes : UK!) address for the RMA
OH.. and I couldn't help myself.. I just ordered a 13000mah battery from DX: http://www.dealextreme.com/p/rechargeab ... ack-110679
They also do a slightly smaller 9600 unit as well. Looking around the web, it seems they are actually the capacity they say they are.. but I'll let you know
(good for me anyway, as I use a USB connection to power my lights as well as all my other equipment lol.