I received the PCBs a couple of days before leaving for EMFcamp, so decided to take the bits along and build it there.
Anyone who has been to a hacker camp before should know that this was a mistake. You never up doing the things you plan, or at least how you planned them!
I decided that the best time to fire up EAGLE and build the PCB was after a few too many drinks, and unsurprisingly it didn't work!
After returning home I gave it another look, and found that I had actually assembled it correctly. So the problem must have been a design flaw. After inspecting some other circuit diagrams, I found that one of the LED's was actually supposed to be used to bias the base of the BJT. A couple of quick mods to the circuit had it working! the V3 circuit should now be correct out of the box.