I have noticed recently that, unlike SWR main line services, SWR metro short forms are rarely reported on journeycheck. The diagram with 458521 did crop up this morning, although the fact that it was only a 5-car was not mentioned directly
06:49 Farnham to London Waterloo due 08:31
Service full and standing from Egham.
I did think that 458521 would do the earlier 0619 Farnham - Waterloo because it only does the 0815 Hounslow loop before dropping out to Wimbledon Park, whereas the diagram it is actually on should stay out all day on Readings before finally ending at Wimbledon Park off 2252 Waterloo - Weybridge.