Pre heat the oven to 150C Fan/170C/350F/Gas Mark 4 and grease and line a 2lb loaf tin
Mix together the butter, caster sugar and the zest of the limes, using an electric mixer or a spoon, until light and fluffy
Add the eggs and milk and whisk in until smooth, using an electric mixer or hand whisk
Gently whisk in the dessicated coconut and the self raising flour, using a hand whisk
Pour the mixture into the loaf tin and bake for an hour, or until a skewer inserted in the centre comes out clean
While the cake is baking, mix together the juice of the limes with the 4 tbsp caster sugar, the sugar will dissolve into the juice while the cake is baking
When the cake is done, poke holes all over it with a thin skewer and pour the drizzle over it, a little at a time until it is all soaked into the cake, using a pastry brush helps with this
Sprinkle the top of the cake with some dessicated coconut, then leave the cake to cool completely
Store leftovers in an airtight container in a cool place and eat within 3 days. You can also freeze this cake if wrapped well for up to 3 months