Hi davy.
Is it possible to swap the whole arm and esc from front to back, or side to side without the soldering. in the video the man mentions about having to solder a wire on esc to flash the bootloader that’s maybe why you can’t get esc’s to be seen.
If not I could only suggest the soldering option unless you have bullet connectors on motors 
if not I’m sure @unmannedtech1 know how to doit 
Thanks perry