Some of you will remember the fun and games I had getting PSU's and steppers to work last week with steps being missed here and there, all now fixed thanks for the advice.
To test things out and make sure no steps were missed, I wrote a piece of software to automatically generate lists of random G0 codes in three axes and then return to 0,0,0. It generates between 10 and 1000 lines of G code in any range you want, available for free download from:
If you only want two axis (i.e. X/Y), simply set the Z 'from' and 'to' values to the same number.