Suspect that it's less likely to be a phone jammer and more likely to be a dodgy microwave oven or something at the distribution park. This would account for the short term interruption that couldn't be detected by the AAIB or OFCOM (if they investigated).
Off the shelf autopilot boards are cheap and reliable (dual IMU, dual GPS etc etc for less than a hundred quid), and could easily take over to return the aircraft towards the site of launch while in a glide descent. Ardupilot can even autoland back at the launch site in the event of signal loss.
Biting the hand that feeds IT
