Greggs is not as easy to find out what is in their foods as some of the other high street companies.
Their websites do not list the ingredients used in their products but if the ingredients in the ones available to buy from supermarkets are anything to go by then quite a few products may be unsuitable for a yeast-free diet.
I emailed them recently and they were only able to give information about the foods I was looking to eat rather than a comprehensive list of what they sell.
I asked about the following four items as I felt that maybe they were some of the most popular choices and I myself used to eat them.
Unfortunately, the following all contain yeast extract:
Greggs Sausage Rolls
Cheese and Onion Bake
Southern Fried Chicken Goujons
The Steak Bake does not contain yeast but does contain barley malt extract. You can read more about why it is recommended that you should also avoid this in my blog post here.
Therefore, it is always a good idea to speak to someone in store about the particular product you wish to eat if you choose to eat at Greggs.