Problems with Z Axis not rising

I am trying to run my spoilboard surface gcode for the first time. Prior to this the ‘Home XYZ’ worked fine and when I ran the probe that also worked fine. My issue is the first time I ran the gcode it stopped and said that the axes were outside the range, even though I set the size according to the supplied information (750 x 750 machine, Spoilboard size 550 (X) x 520 (Y) ). I reduced this to 540 x 510 and got the same message. I tried to ‘Home XYZ’ again, the X and Y homed but not the Z. The Z just wanted to keep going down. It shows the idle positions as 0 for X, Y and Z but a work position of X - 0, Y - 0 and Z - -94. Every time I try to ‘Home XYZ’ the same thing happens and I have to hit emergency stop before it breaks the Z axis. How can I reset the Z axis to 0? or reset everything?

Many thanks