Bring milk to luke-warm temperature. Melt butter and allow to cool. Measure butter, sugar and rum. Finely chop peel. Preheat oven to 400 degrees F. Warm bowl. Place the sifted flour into the warmed bowl and make a well in the flour. Add the crumbled yeast, 3/8 cup of the milk, the sugar and salt. Mix until the yeast has dissolved and then add the eggs and beat with the hands until well combined and smooth. Cover the bowl and put into a warm place for 45 minutes so that the mixture will prove. After 45 minutes remove the bowl and add the cooled, melted butter and the remaining 1/4 cup milk. Beat hard for a couple of minutes and then half fill 4 greased small cake molds. Cover the mold and place in a warm place for a further 10 minutes. Place the mold with the risen mixture into the oven and cook for 20 minutes. Unmold onto a cake rack and allow to cool a little. Place the butter with the sugar into a frypan and stir to form a fudge - add 1 tablespoon of rum and the sultanas, peel and grapes. Coat in the fudge mixture. Place the babas in the fudge mixture - prick lightly with a fork and turn in the sauce. Pour 2 tablespoons of rum over each baba and then set alight. Place individual babas on serving dishes - cover with the sauce and serve accompanied by the whipped cream.