Interesting thread. (And as Andy says, an excellent Spectrum John).
I’m not sure what the relationship is between ISIS and Demetra code (that is, whether ISIS code/logic has been reused) but just out of interest I’m still having a little tussle with higher order polys in Demetra calibration. Lower orders are fine and produce excellent results. Anything above three and I sometimes get very strange results.
Rgds
T