Yes! The manufacturer claims that this product is vegan, making it suitable for pescatarian eaters as well.

Is M&S Food Made Without Wheat and Gluten All Butter Shortbread Rounds Pescatarian?

Yes! The manufacturer claims that this product is vegan, making it suitable for pescatarian eaters as well.
Pescatarian? M&S Food Made Without Wheat and Gluten All Butter Shortbread Rounds | Spoonful