Hi everyone, first post!
I recently installed an Edge controller and Reach M+ into a hexacopter build and could not get the 2nd GPS data feed to work in Mission Planner. After hours of experimentation I found the error in that the output from the Reach M+ was connected to the Edge SER2-ADC as illustrated in the documentation, however the written instruction states SER1-12C.
If you have the same problem, follow the written instruction and use the SER1-12C, it will work fine.