Tip the bread mix into a bowl and stir in spice and sugar. Rub in the butter with your fingertips. Stir in the peel and currants.
Pour 100ml/4fl oz water onto the milk, then beat in the egg and pour into the dried ingredients. Mix to a very moist dough (the wetter the better). Leave for 5 mins then cut in to 10 equal pieces and roughly shape into buns with oiled hands (this helps to stop the mixture sticking too much). Even though the mixture is very moist, try not to use extra flour as it will toughen the dough.
Space the buns apart on 2 greased baking sheets, cover loosely with cling film, then leave in a warm room until about half again in size. This will take anything from 45 mins to 1 hr 15 mins, depending on how warm and moist the environment is.
When the buns are risen, heat oven to 220C/fan 200C/gas 7 and make the crosses. Mix the flour with 2½ tbsp water to make a paste. Pour into a plastic food bag and make a tiny nick in one of the corners. Pipe crosses on each bun. Bake for 12-15 mins until risen and golden. Trim the excess cross mixture and brush with golden syrup. They’ll keep fresh for a day, and after that are best toasted.