CatVH - I have mentioned before that I use bustimes.org. That gives me real time data at every single bus stop for every single bus literally from Lands End to John O'Groats, so you can get huge advance notice of any issues.
It even tells me the registration of the vehicle, it's type and normally a photograph of the bus.
There is a vast amount of data. It is what is used by the Traffic Commissioners to monitor operations and is the brains of the ticket machines, which tell the driver to the second if they are early or late.
It is available for months afterwards.
Personally I have traced missing buses round the country many times that way, as long as I can get wifi, as I don't have (can't afford) a smart phone.
I have been analysing what happened tonight. The inbound buses terminate at York Way, then run empty on layover round the back of the railway land and re-enter service on Pancras Road. Those buses not turned tonight by control at Farringdon got to York Road, but were then told,.one assumes by control, to turn right at the Hub PI KC, back to the Old Scala cinema to re-enter service just after KC. Very few went round the back.
I used this this data source a few weeks ago for a forum member going from Keswick to Penrith. The data feed showed me the bus was delayed in roadworks on its previous journey to Workington. So I told her in real time to catch the bus 30 minutes earlier (also delayed) so as to not miss a train to the Cotswolds.
The irony is I had been tracking Jules' train since 7am today for any issues.
I know it got to KC 4 minutes 45 seconds late.
But not watching the buses.
Had the original advice been followed to use the train from St Pancras via London Bridge for the same price as a tube fare using contactless she would have left St P at 1930 on an 8 or 12 car train, arrived at London Bridge on Platform 4, switched to 8 or 9, and reached Waterloo East at 1949, 1953 or 1959 depending how fast the change was made, so have been in the hotel over an hour sooner.