My only question would be how much notice was given for the cancellation of the following Hereford WMT service? Realtimetrains doesn't help much, but the lack of reports and a cancellation note perhaps hints that it wasn't much!
I did check in Liverail, which has mere detail including the time a message is posted, but I think that relies on
TRUST▸ alone. And, as openraildata.com says:
If a train is to be cancelled en-route, although the cancellation can be entered in to TRUST in advance, no cancellation message will be generated until the train has arrived at the point from which it is cancelled