The German StVZO regs are very good and the most stringent in the world AFAIK – all my lights are German and they’re much better for the road than any UK light – and I doubt you’d run into any trouble convincing a UK court that such a setup is legal. The only tricky bit is pedal reflectors. When using clipless pedals I use reflective tape – but it’s white.
“It’s certainly been used before, there was one definite example where a judge ruled 25% contributory negligence from the cyclist for not wearing a helmet. I can’t find the case at the moment though but it’s a very dangerous precedent.“
Wasn’t that the one where the chap was on an organised (and, IIRC, competitive) company event and refused the helmet he was asked to wear, then himself caused a crash and sued the company? (Or something like that.) – If so I *think* the contributory negligence bit was due to his refusal to heed their specific advice rather than for simply not wearing a helmet per se.
But even if contributory negligence has not managed to actually reduce damages, there is precedent of the consideration that it (in the eyes of the law) does so, which is the Smith v Finch case:
http://www.independent.co.uk/news/uk/home-news/outrage-at-ruling-on-helmets-for-cyclists-1645736.html
http://www.cyclistsdefencefund.org.uk/smith-v-finch-jorgensen-v-moore-reviews-cases-involving-cycle-helmets-and-contributory-negligence
http://www.access-legal.co.uk/legal-news/cycle-helmets-a-legal-update-lu-3863.htm
So, there is a clear risk of damages being reduced for not wearing a helmet even in a non-fault incident. I think it’s massively misguided, but there you go.