Preheat the oven to 180ºC/350°F (fan forced).
To make the dough: combine the flour, baking powder and sea salt. Add the butter and either rub into the flour by hand or process until well combined with the flour (to form a crumb). Add the milk and mix until a firm, slightly sticky dough is formed. If it is too sticky, add more flour or to dry, add a little more milk.
Roll out between two pieces of baking paper into a 1cm thick (roughly) rectangle.
Remove the top piece of baking paper and scatter the filling evenly over the dough then roll it up into a cylinder. Trim the outer doughy edges and cut into approx. 2cm wide slices, carefully placing each slice onto a baking tray, leaving a little room between each one (they will expand).
For the syrup: combine the sweetener and hot water and mix until the sweetener has dissolved. Drizzle over each roly-poly.
Bake for 40 minutes or until the dough has risen and browned slightly (and most of the syrup has reduced).