Andrew Chesters wrote:

Going a bit further OT, I saw some cat's eyes that I could see
illuminated in my mirror after I had passed them. No, nothing coming
the other way! Anyone know anything about these?

Yes, they're the ones I'm on about. The usual blueish tinge typical of
"white" LEDs, they seem to be powered on about a 50% duty cycle so they
appear to flicker as you pass them, conserving power in their super
capacitors I suppose ... surprised nobody seems to have nicked any of
them (yet)