M40 & M41 do not work

[Bluebell]

I have GCode to record Z for an array of points to use for input to AutoLeveller. The Output file name is set in the UCCNC digitising page.M40 is at beginning of GCode and M41 at the end.

The code steps through the array and (G31) appears to measure Z. But, no output file is recorded.

In my installation is listed as MPG multiplier to 50, and M41 is absent without leave.

Note that GCode generated by the UCCNC Leveller macro has no M40/41, so I assume commands to open and close the file are hidden in the macro dll.

Suggestions to fix this please.

Bluebell