I wouldn't worry too much about legality. Even if it is strictly against the law, the chances of being convicted must be vanishingly small and, if it does happen, what do you get - a fine of a few quid? Take the motorist approach to fines and regard it as a small "Tax on Christmas".
I would think a bit about safety, though. Red lights at the front may confuse people etc. Drivers are dangerous enough in perfect conditions. OTOH, going about literally lit up like a Christmas tree may help one's conspicuity, I suppose.