Grease an 18cm loose-bottomed, deep cake tin and line the base with baking parchment if needed. Mix the digestives and the butter until evenly combined.
Use a straight-sided glass to press the crumbs evenly across the base of the tin, and place in the fridge to cool for 20 minutes.
For the filling, combine the cheese, sugar, the lemon juice and the zests evenly. Heat up the filling mixture in a microwave at medium power (300W) or in a bain-marie until reasonably hot (60°C/140°F).
Dissolve the gelatin on milk as per the package instructions.
Combine the gelatin milk with the hot filling mixture, and pour over the biscuit base. Chill for 4 hours, or even better, overnight.
For the topping, combine the strawberries with the sugar, leave it to macerate for 20 minutes and use it to decorate the cake before serving. Slice the kiwis and decorate too.