So I made some progress in that I realised there's actually another part of the head of the light which un-screws. Unscrewing this has given me access to the driver itself.
In doing that, the problem is obvious - the board has been broken when the head has been screwed back on, it looks like a pretty crappy design.
Here's the section with the driver, showing how it was as I opened it: http://t.co/NBa46cKY
And here's after de-soldering the remaining leg holding the two pieces of the driver together: http://t.co/pv6TIp6P
I don't see how I can fix this myself as it looks like the copper tracks on the board are now missing, hence re-soldering it would not work, am I right?
..just me or the TR-J12 with LED's re-wired in series, equipped with either http://www.kaidomain.com/product/details.S020077 (cheap, but as it supports only 4 LEDs, center one would have to be disabled) or something like TaskLED Hyperboost (more expensive, but way more functional), and three A123 LiFePO4 26650's would be most lumens/$? :P
Surely it sounds just like a dream, but I'll try to implement that dream in reality as soon as I get it - it's marked as shipped for two weeks already, but China post has some weird randomness factor with delivery times - that KD driver (as well as six 26650's) arrived few days ago, while being ordered same day as flashlight.
I'm currently doing battle with DealExtreme customer services, took them three days to respond to my initial query and their response was "check the forums for more information".
Not terribly useful, no amount of forum checking is going to solder the driver back together *sigh*
By the time I have a working flashlight there's going to be a new emitter out and this one will be a relic!