I am trying to find a source of the above poppy, which comes in single and double. It re-seeds itself and does well in this area. Can anyone give me some help please?
I think what you are looking for may be known by another name. I couldn't find anything called Poppy Bread Sweet. I found Poppy Sweet Bread, but it's bread, not a poppy seed.
If you are looking for a poppy that produces seed used in baking, that would be papaver somniferum. It comes if both double and single, has been hybridized to produce ornamental cultivars, and can be grown from seed. You might also find it called "breadseed poppy." Once you know what you are looking for, you won't have trouble finding seed. Many seed catalogs carry it. It is the same poppy that is used for opium production, but that is obtained from the plant's sap, not the seeds.