Again, this site lists the common allergens in their foods. I got in touch to find out more.
I had a reply from a lovely lady who informed me of the following products that use yeast in the ingredients.
Avoid list:
All Beanie meals
All Rolls
Pitta breads
The Great Imitator meals
Mushroom & halloumi meals
PERinaise
Garlic PERinaise
PERi salt
Quinoa & PERi-Tomato Salad
Lemon & Wild Garlic dressing
All beers/Ale/Cider