Lightly grease a 20cm springform pan and line the base with baking paper.
In a saucepan, cook blueberries with 50g sugar and half the lemon juice over medium heat for 7 minutes until soft.
Set aside 4 tablespoons for topping, then cook the rest until thick and jam-like. Blend until smooth and let cool.
Crush biscuits into fine crumbs and mix with melted butter. Press firmly into the pan base and slightly up the sides. Chill for 30 minutes.
Beat cream cheese with remaining sugar, vanilla, lemon zest, and juice until smooth and thick.
Whip double cream until stiff peaks form.
Fold blueberry purée into the cream cheese mixture, then gently fold in whipped cream.
Spoon filling over the crust and smooth the top.
Chill the no bake blueberry cheesecake for at least 2 hours (or overnight).
Before serving, top with reserved blueberries and slice into wedges.