Currently I don't think there is a straightforward way of doing this; but you could concatenate the 4 gcode files together, and make sure there is no M0 command in the end gcode of each file.
Found the immediate problem. Rookie mistake. I checked the colouring of the BLT ground wire and it changed from black to blue when it went through the Tevo connector to the board, which meant the Z probe wires were switched.
