Check if it contains folate - that seems to be the issue. It's added to Vegemite - maybe it isn't added to Marmite.
I wouldn't be at all surprised if Kraft starts manufacturing a folate free Vegemite for export after this - the amount in it is absolutely tiny.
Marmite.
Ingredients:
Yeast Extract,
Salt,
Vegetable Extract,
Niacin,
Spice Extracts,
Thiamin,
Riboflavin,
Folic Acid,
B12.
Nothing about folate.