I agree that it is an excellent system, and have enjoyed using for close on 18 years now, but we must be open enough to review options.
That doesn't mean that the lack of an operator should spell disaster though. A series of fixed green and ambers at crossing points for caution and reds for runway entry points would be sufficient. Cross amber with caution, obey all reds.
That would work just as well, as it does virtually everywhere else around the world. The size of LHR is I believe a red herring - the complexity of JFK is equally great (not that I'm suggesting stooping to that level!).
The analogy is to the continent where after the evening rush hour the traffic lights are changed to flashing amber to advise caution - why can't the nanny UK state adopt that principle - quite often when the lights fail, the traffic does a better job itself anyway.
I would rather you pushed for leaving the stand guidance on permanently to allow us to park without blocking taxiways than keeping the red/greens switcheable.
Do you remember the fuss when they got rid of all the Block numbers at LHR? Who misses them now - anyone 'fess up to that? Not me.