First, thank you for your reply
The receiver I used is taken out of my Diatone Marauder M515 Ultralight, so know it works. Blue and green light S.Bus.
Then pin in on the FC is from a F3, is the GT-M5 a F3S? I’ll give it a go and get back to you.
Found this vid, jump to 21.32 Diatone M530 Stretch Review | Unboxing | FrSky Receiver Install | Drone of the Year - YouTube
So by the diagram above I’ll be using the S.Bus on the F3 which is the 3v on the F3S. Not sure if I want to do that.
Anyone else have the same prob with their GT-M5?