Here are the details of maps for Purley (E):
This map covers the eastern part of Purley, including the Brighton Road, Christ Church, Purley Oaks, Haling Lime Works, Purley Downs, Briton Hill. Stretches of the LBSCR main line and East Grinstead line are shown, incl Sanderstead station. The map is double-sided to include part of the very rural Sheet 20.03, covering Sanderstead Court, All Saints church and Sanderstead Plantation.
You might find this Index map useful. The map links up with Surrey Sheet 14.14 South Croydon to the north, 20.01 Purley to the west.