So I have been checking I have everything in order before stripping down my Bigbox to move over to Titan extruders. The only thing I hadn't checked was that the stepper motors I had bought were working. I had bought OMC 17HS10-0704S pancake motors which had the same plug and socket as the existing motors. I powered down and disconnected the Y axis plug from the stepper and plugged in one of the pancakes. On powering up and trying to move the stage it shuddered but didn't move. Trying the original motor resulted in no movement. I replaced the Y axis driver with the second extruder one and it was back to working. After ordering some replacement drivers I tried again with the same result. On further examination I have found that whilst the cable colours are the same, two of the cables are swapped around.....so much for standardisation. Rewiring the connections had the new steppers working. Hopefully this will save someone else so pain (and drivers).