Colins cheesecake mousse with crumble and berries

Name: Colin's cheesecake mousse with crumble and berries
Ingredients: 250g cream cheese, at room temperature, chopped; 100g (1/2 cup) caster sugar; 1 vanilla bean, split, seeds scraped; 250ml (1 cup) pouring cream; 90g (1/3 cup) creme fraiche; 2 tablespoons lemon juice; 1/2 lemon rind, finely grated; Fresh mint leaves, finely shredded, to serve; 150g (1 cup) plain flour; 75g (1/3 cup) demerara sugar; 75g butter, cold, chopped; 40g (1/4 cup) slivered almonds; 40g (1/4 cup) pistachios, chopped; 40g (1/4 cup) sunflower-seed kernels; 250g mixed fresh berries; 2 tablespoons brown sugar; 2 tablespoons good-quality red wine vinegar; 50g fresh ginger, peeled, cut into matchsticks; 215g (1 cup) caster sugar; 200ml water