We have two English/Dutch speaking guides in the area and two guides who only speak Spanish.
English and Dutch speaking:
Discover-extremadura.com (bird-watching and nature guides with focus on Villuercas Ibores Jara)
Near Cañamero, on the entrance road to the Cancho del Fresno Reservoir, is the ZEPA information Centre. The opening hours are Wednesday trough Sunday from 10 AM to 2 PM. But information is only available in Spanish.