Using an electric mixer fitted with a paddle attachment, combine all the dry ingredients (A) in the mixer bowl, and mix well.
In a separate bowl, combine all the wet ingredients (B). Fit the electric mixer with a dough hook attachment, then add all the wet ingredients (B) to the flour mixture (A). Knead on medium speed (speed 3 on my Kitchen Aid mixer) until a rough dough comes together.
Add (C), and knead on medium speed until dough becomes smooth and elastic. Add (D), continue to knead to incorporate raisins in the dough. Turn out dough and remaining loose raisins, onto a lightly floured work top. Finish up kneading by hand, using lightly floured hands (dough will be slightly sticky) if necessary, until all raisins have been mixed into the dough.
Place the dough in a lightly oiled bowl, and set aside to ferment for 50 to 60 minutes in a warm, draft-free area (the inside of an oven, for example), until doubled in size.
Meanwhile, prepare the crumble topping. In a small mixing bowl, combine flour and sugar. Rub the butter into the flour-sugar mixture, until the mixture resembles coarse breadcrumbs. Refrigerate until ready to use.
Divide the dough into 15 to 20 g portions, and mould each into a ball. Place the dough balls into a greased loaf tin (L20-cm x W10-cm x H8.5-cm). Set aside, covered, to proof in a warm, draft-free area for 45 to 60 minutes. Meanwhile, pre-heat oven to 175 deg C (350 deg F).
When dough has risen to, or just above the edge of the loaf tin, it's ready to be baked. Brush the top with egg wash, and sprinkle with crumble topping.
Bake at 175 deg C (350 deg F) for 25 to 30 minutes. When done, turn out loaf onto a cooling rack and let cool completely. Slice and serve as desired.