Renault Espace (2004) Parking Brake fault?

My dashboard instrument panel is displaying the "SERVICE", "P" (within a triangle) and parking brake warning light. When turning off the ignition, there is a delay before the automatic parking brake engages. Once the parking brake engages, the actuator unit (long rectangular box in front of the fuel tank) makes a very audible ticking sound.

Does anybody know if this can be repaired without paying main agent prices and where a new/refurbished unit can be purchased from.

Gordon, Lowton
September 2009