So during an autonomous flight on GPS and the copter lost its fix and went to failsafe and landed, into a fence unfortunately.
I took the copter in for inspection and powered up to verify all was functioning correctly however there was no tone from the ESC's. I connected each ESC to the receiver individually to ensure the receiver, ESC's and motors were all functioning correctly and they all were.
The flight controller will arm and pre-arm checks are enabled therefore all of those parameters are safe however even after arm no signal is sent to the ESC's and/or motors. The FMU has a Solid blue LED and a flashing red LED after the start-up process has finished.
I have no idea what to look for now I have checked everything I can think of.