Grease a 8-9 inch cake pan. Add all chips, milk, vanilla to large heavy pot over low heat, melt, add currants and walnuts. Wrap the empty condensed milk can with plastic and place center of pan, fill pan with fudge. Do not smooth the top – let the wreath be bumpy and irregular in surface. Decorate with cut red and green cherries to look like holly bunches and chill. Remove from pan, remove can, platter and serve in very thin slices.