AFAICT from previous announcements [and the SL RUS], from the May 23rd
changes these services split/join at Purley to reduce the numbers of paths
used into London Bridge.

However journey planners seem to show a change at Purley for all ex Caterham
services, wouldn't they normally show a service that joins all the way
through to a the final destination in 'public facing' systems and printed
timetables?

I expect that one of the trains will disappear from the 'internal systems'
at Purley, so this seems to be cockup rather than conspiracy...

Paul S