Put the cream, 50g sugar and orange zest in a saucepan and bring to the boil for 3-4 minutes, stirring to dissolve the sugar. Remove from the heat and stir in the coconut milk.
Put the gelatine leaves in a bowl and cover with cold water. Sit for 5 minutes until very soft. Remove the gelatine, squeeze out the excess water and stir into the coconut cream until completely dissolved.
Lightly grease 4 x 175ml ramekins with sunflower oil and place on a tray or flat plate. Pour the mixture into the ramekins or moulds and place in the fridge for 2 hours until just set.
Meanwhile, heat the remaining sugar in a small frying pan. Slice the pith from 1 orange, then cut the flesh into round slices and add to the sugar. Cook for 1 minute until caramelised, then turn and cook for another 1 minute. Serve with the pannacottas, drizzling over the remaining caramel.