CCLDB is a really handy web based way of quickly checking all arrivals/departures for a station or a particular journey, it shows platforms when confirmed, ECS moves, updates and uses Darwin as a feed to display actual services during disruption.
I believe it was initially designed for National Rail Enquiries Call Centre, but couldn't confirm. I look it as an easier on the eye version of Location Enquiry on TRUST.
CCLDB = Call Centre Live Departure Board. There's also Historic LDB which can show you historical info on departure screens. Very useful in disputes.
I always preferred RTT or equivalent as you can send the link to the passenger and show them how it works.