I am using a unity and two Sesored Sk3s powered by a diyeboard 10S3P pack.
My motors are spinning in different directions, I have swapped the phase wire on the one going backwards and it doesn’t seem to solve the issue.
Is there a setting I’m missing?
You should only swap 2 wires on the motor that is backwards. Any 2 wires on the motor. It should fix the issue. You can also swap the direction of the motor spin in the software under the motor calibration tab on the focbox unity software.
You can change motor direction with the red marked symbol. Just tab it or click on it. 
That worked, cheers