I read it differently. My interpretation is any black station to any red station.
Travelling into London:
From any of the following stations on the South Western Railway network: Weymouth, Upwey, Dorchester South, Moreton, Wool, Wareham, Holton Heath, Hamworthy, Poole, Parkstone, Branksome, Bournemouth, Pokesdown for Boscombe, Christchurch, Hinton Admiral, New Milton, Sway, Romsey, Mottisfont & Dunbridge, Dean, Salisbury, Warminster, Tisbury, Gillingham, Templecombe, Sherborne, Yeovil Pen Mill, Yeovil junction , Castle Cary, Bruton, Frome, Westbury, Trowbridge, Bradford on Avon, Crewkerne to London zones 1-6 stations: Barnes, Barnes Bridge, Berrylands, Brentford, Chessington North, Chessington South, Chiswick, Clapham Junction, Earlsfield, Ewell West, Feltham, Fulwell, Hampton, Hampton Court, Hampton Wick, Hounslow, Isleworth, Kew Bridge, Kingston-Upon-Thames, Malden Manor, Mortlake, Motspur Park, New Malden, Norbiton, North Sheen, Putney, Queenstown Road, Raynes Park, Richmond, St. Margarets, Stoneleigh, Strawberry Hill, Surbiton, Syon Lane, Teddington, Thames Ditton, Tolworth, Twickenham, Vauxhall, Wandsworth Town, Waterloo, Whitton, Wimbledon, Worcester Park
Also wasn't it £15 return last year?