Hey Sheza!
They are flaxseed yes, as these are slightly larger than the others.
There are upper limits of vitamins and minerals, however, these are far higher than the recommended nutritional levels. There are other Huel users consuming more than 2000 calories, for example: 100% Huel for 1 month - 2000-3000 Calories & toilet trips
It doesn’t become very nice if you leave it for a long time unrefrigerated, so I wouldn’t want to consume it if I were you!