Hughesy is right thats middle bacon. If he is a good butcher then he may have felt that, that made the best use of what might have been a fatty carcass. Most people have an idea of what amount of eye they expect to see on a slice of commercial, intensive farmed back bacon. If our pig didnt have that sized cut then he ma have been trying to create more value in the product by leaving the tail on.
Good butchers are hard to find and the butcher represents at least half of your products value and visual appeal so work with him and with the carcasses that you send.
It sounds like its your first time so there is chance to get it right for the next one.