This is bollocks
When Countdown was first implemented in the late 90s, I was working tech support on the system. The reason it's not GPS (which was tried) was due to the number of tall buildings in close proximity and innacuracy. Instead, they used a system of beacons on buses that talked to street beacons, so that the system knew, every time a bus passed one, where it was.
In testing, it worked... perfectly. In practice it failed and does now. The reason is NOT due to it showing when a bus is timetabled to arrive, not y any means. The real reason is this. 99% of the "failures" were fixed by the engineers removing the foil, tin cans, crisp wrappers etc that the drivers had pushed in front of the lens to confuse it so the system couldn't track them. It failed because of sabotage, and I don't mean just pushing it down the side of the seat, this was way above eye level.
The onbly way this will ever be fixed in London is to remove the drivers from the equation, and we can guess where that will end.