Clive - that's a very kind offer but I have just ordered 4 more which should be here by the end of the week. For the moment, I can get by with homing each axis in turn (using the buttons on the Diagnostics page). I home one axis, then jog it a tiny bit away from the home position. Doing each axis in turn like this is a bit of a chore but it does mean that I can continue with testing. Next job is to sort out squaring the gantry and then test my ideas for dual-motor homing using an IP/M which does not support this.