Customers buy domain names s they can use them with their wesites. BT should make it a standard that all eShops should utilise and present the customer preferred domain name rather than the //eshop.domainname.com/ etc.
It is possible to change your shop to point straight to your domain name, however we haven't made this the default as we want to give everyone the choice of both options.
For more info see the Help & support FAQ about pointing your domain directly to your eShop.