Crumble yeast into a small bowl, add the teaspoon each of the first measure of flour and Chelsea White Sugar. Mix in the milk which has been cooled to blood heat, cover and leave in warm place for 10 mins.
Sift the second measure of flour, salt and spice into a large bowl; rub in the butter and add the second measure of Chelsea White Sugar and sultanas.
Add the beaten egg to the sponged yeast mixture and beat into the flour mixture until a soft dough is formed. Knead until light and smooth and no longer sticky.
Place dough in a lightly oiled bowl, cover with plastic wrap and a clean cloth and allow to stand in a warm place until double in bulk (about 40 minutes).
Turn onto a lightly floured surface, punch down and knead dough until smooth and elastic.
Divide dough into 16 even-sized pieces - knead each into a round shape. Place on a greased slide tray 1cm apart. Cover and stand in a warm place until well risen (about 10-15 mins).
Mix sufficient cold water into the flour to make a soft paste and pipe a cross on each bun.
Then bake at 220°C conventional (200°C fan forced) for about 20 minutes.
Heat the Chelsea Caster Sugar, water and gelatine in a saucepan and simmer 1 minute.
When the buns are cooked glaze them with the gelatine mixture while still hot.