They're just called Belgian Booted Bantams. d'Uccles have beards and muffs. d'Anvers dont have boots.
There is no such breed, there are Belgian bearded bantams (d uccle, d anver, d grubbe, d watermeal etc). These birds are definitely sablepoots ( booted bantams which were developed in England, Germany and the Netherlands. they were used in Belgium to create the d uccle