Finely grate the zest from one of the limes and squeeze the juice from both. Put in a small pan with the sugar and heat gently, stirring to dissolve the sugar. Add the blueberries and simmer for 2 minutes, just until the skins start to split.
Pour the blueberry mixture into a bowl and stir in the coconut cream. Leave to cool. Whip the cream in a large bowl until it just holds its shape, then gradually stir in the blueberry mixture. Put the bowl in the freezer for about 1 hour, until the mixture is set about 3cm in from the edges.
Remove from the freezer and mix it all together using a whisk. When it’s fairly smooth, return to the freezer for a further hour, then repeat the whisking one more time. Transfer the ice cream to a rigid container, cover and freeze until firm, or for up to a month. Before serving,move to the fridge for 30 minutes to soften it. Serve with extra blueberries scattered over.