I dropped an email to the Tourism Post at the Oficina Municipal de Turismo in Estepona about services between Seville and Estepona.
Their reply was as follows:
"Para llegar desde Estepona hasta Sevilla debe usted tomar dos autobuses: El primero desde Estepona hasta San Pedro de Alcántara, y el segundo desde San Pedro de Alcántara hasta Sevilla. Para el trayecto a la inversa el recorrido es el mismo. Para más información acerca de horarios, duración del trayecto y precios, le ruego visite la página web de la compañía www.ctsa-portillo.com donde encontrará toda la información de autobuses de la zona."
For those who don't do the Spanish:
"To get from Estepona to Seville should you take two buses: the first from Estepona to San Pedro de Alcantara, and the second from San Pedro de Alcantara to Seville. For the journey in reverse the route is the same. For more information about schedules, travel time and prices, please visit the company www.ctsa-portillo.com where you find all the information on buses in the area."
As the Faro to Seville winter timetables are not yet out, we can only surmise but based on last years winter schedules, the following routing may be possible:
Faro - DAMAS/EVA bus to Seville Plaza das Armas
Dept: Around 09:00
Arr: Seville Plaza das Armas circa 14:00 (Spanish Time)
Local C4 Bus to Estacion AutoBus Prado
ctsa-portillo bus - Seville Prado to San Pedro Alcàntara
Dept: 16:00
Arr: 19:20
ctsa-portillo - San Pedro Alcàntara - Estepona
Dept: 19:30
Arr: 20:05
or
Dept: 20:00
Arr: 20:35
Note all times are based on previous knowledge and existing timetables and may change with incoming winter timetables.