Grandad, I know I should have used resistors for the front LEDs - that's why 3 of them started flickering and died - but I've gotten away with not having to use resistors since I dropped the output voltage of the regulator to 3v exactly, since then I've not had any more do the 'death blink'.
However I do miss the extra brightness that 3.15v gave so I'm thinking of re-doing the front light with 30x 3mm LEDs as I should be able to squeeze that many (perhaps more) into the reflector and the beam spread is more pleasant, in that it has a more even decay from the center rather than the round spotlight of the 5mm LEDs.
Now it's getting darker quicker and the weather is turning for the worse I'll finish off my current setup, and do the photo & diagram thing so others can see what I've done. After that I'll look at re-doing the front light as the back one is certainly bright enough with 4x LEDs mounted behind the reflector, most vehicles give me plenty of room when overtaking
