You can apply for DSA.
You should be aware however that generally DSA covers specific costs you incur because of your disability AND studying.
You'd have your dietry requirements whether you were a student, living at home, or working, so its unlikely you'd get any help with your food costs. That said, there are many who would say that you wouldn't need to buy things like your own cooking equipment if you weren't living in student accomodation so DSA may help you with the costs of those.
Ditto, any extra time or breaks during exams can be arranged through the Needs Assessment, or provision to make like easier if you are ill or miss classes more than other due to problems associated with being Coeliac.