Here is my Idea:
Establish a website and APP that allows you to access information about "Free From" food sources in a specific area

I know a number of coeliacs and people who for other medical reasons are becoming very knowledgeable about the types of food they can eat and where they can source them. It would be fair to say that when people with specific dietary needs go out they will be fully aware of their limitations. However, it would also be fair to say that armed with easy accessible information that they can get from their phone or electronic device they are carrying, they would make more informed and specific choices. It is the easy access to this when you are out or on holiday that would make it a winner I think.

I think people with specific dietary needs settle for limited choice, or no choice at all rather than:

Wander around a town constantly asking: do you do gluten free or dairy free or.......

Spend hours on the net looking for restaurants / tea shops looking for suitable places.