Well, the RLJ'er today had the right idea as the opposite flow turned green but me and another cyclist sat obeying the red, which never changed, so the crossing traffic got to go again.
On the second time around, when the opposite facing flow started to move and yet again we had the red light, we said "sod it" and set off.
It was notable that we had sat through a light change with no other traffic, so had something to make that decision with, as knowing the lights, there was enough to say the lights were faulty.
The taxis, who had appeared after the last "failed change", set off too and followed through the red. Maybe they realised why we were going through, but if so, that's encouraging, they didn't think we were just ignoring the lights "like all cyclists do".
Or maybe all taxis do anyway.....