So, we have established that Esher and Walton are out of use and have been for years which certainly looks to be the case.
However, New Malden can be used, presumably if engineering work or some other inconvenience affects one or both of the slow platforms. Which begs just one further question; given that the indicator boards had been left, or put, on the fast platforms, why have they recently been removed?
http://www.railforums.co.uk/showthread.php?t=28839
Back in 2009 a thread suggested that they had just removed the info displays at New Malden's central island, but someone else mentioned in the same thread that it remained available for emergency use:
The platform has a surface you can walk on but isn't made up of slabs or tarmac etc like in use platforms.