thanks for your reply ,we are well aware of all the related problems but still have various opinions on the topic that concerns us, what would be your view bearing in mind that the markings are on the fur not the skin

How can you be more concerned on the colour of her fur than on health ?

The breed standard calls for a white blaze and any tan marking on this would be a mismark. I have only a general interest in the breed, having considered owning one myself some years ago and so I would still encourage you to join the breed club and become involved with experienced breeders as these beautiful dogs have more than their fair share of genetic problems.