According to Airframer.com, the suppliers to theWatchkeeper Programme include:
Advanced Composites (prepregs, MTM 46 epoxy prepreg system)
Lola Composites Ltd (Fuselage manufacture, Composites Manufacturing Services)
Salex Galileo SpA (Surveillance/Air Defense Radar: Gabbiano T20 Radar)
Rockwell Collins (Attitude and Heading Reference Systems: Athena 411 integrated inertial navigation, global positioning & air data attitude heading reference systems)
UAV Engines Ltd (Rotary Engines)
This does not appear to be new information, except perhaps the addition of supplier Salex Galileo, which appears to have gained the contracts to supply both Watchkeeper and Israeli Hermes 450 and 900 with radar technology. A lengthier list of suppliers can be found by searching earlier entries of this blog.
UAV Engines Ltd is an Elbit subsidiary, and appear to supply rotary engines to other Elbit drones manufactured elsewhere.