The tracking on 'bustimes' in theory shows scheduled / actual times, although (from a small number of samples) the data seems a bit inconsistent.
An example from earlier today. (if this doesn't work by the time you see it, go down to 'vehicles' at the bottom of any timetable, select a vehicle then a journey.)
I can't immediately think of any others that show scheduled / actual for specific journeys, just sites that show where individual buses are or predict when they will arrive at the next stop.
And at the risk of stating the obvious, on any route that's considered 'high frequency' they are regulated by controllers to run on headway basis, even though there is a schedule in the background for each bus. From the perspective of passengers, and of TFL's monitoring, it doesn't matter if every single bus is in the 'wrong' place so long as the service is running at an even headway. (Although obviously there are practical issues when it comes to drivers' hours and breaks and so on)