I received the first replies to my vegan friendly (alcohol) marker inquiries.
Since Winsor&Newton’s acquisition of the Letraset Marker was fairly new and their information sheet existed exactly in its same form before that, I put this concern in my mail. Colart replied for Winsor&Newton that they are checking their supply chain for animal derivative contamination of the raw material. However, Winsor&Newton and Colart are cruelty-free and Colart confirms that chemically the majority of the raw materials used, is free of animal derivatives.
Here is said information sheet : Winsor Newton Animal derived ingredients list
Source: Mail contact