You could try giving them your company tax number. In most cases, if you did register for Vat, the same number would be used by Revenue.
Would there actually be vat on the items your company is selling? Many food items are zero rated. If not, the argument that you are dealing mostly with the end customer rather than business clients, and would have to charge higher prices due to Vat, doesn't hold.
In addition, you would be able to lower your costs by reclaiming the input vat on business purchases. It is more hassle, but could be economically the right thing to do.