Issue resolved thanks to King Arthur.

I had started a full Py including HT a few months back, before deactivating HT and starting a new game without HT. Kicalk was left over in some recipes. Loaded mod provided by KA plus ran script, all fixed.

Thanks for the support!

I seem to have got my metaphorical knickers in a twist. I have all Py mods enabled except for High Tech. I have got the alternate Chemical science pack recipe (using 1000 Oil) going to get started, but need to get the direct one going. It requires Good Alien Samples, which require Korlex Milk which ...