Melt the butter in a saucepan with the golden syrup, then stir in the biscuit crumbs and mix well. Tip the mixture into a greased 20 cm (8 inch) springform tin and press over the base and two-thirds of the way up the sides with the back of a spoon. Chill.
Scoop the soft cheese into a mixing bowl and break down with a spoon. Stir in the fromage frais, sugar, lemon rind and vanilla essence, then gradually mix in the lemon juice until smooth.
Whisk the cream in a second bowl until it forms soft swirls, then fold into the cheese mixture. Pour into the biscuit-lined tin and spread the surface level. Chill for 4–5 hours or overnight until firm.
Warm the frozen fruits in a pan with the measured water and sugar for 3–4 minutes until defrosted. Blend the cornflour with a little extra water, add to the pan, bring to the boil, stirring, and cook for 1 minute until the sauce has thickened. Leave to cool.
Loosen the edge of the biscuit case when ready to serve, unclip the tin sides, lift off the base and transfer the cheesecake to a serving plate. Cut into wedges and serve with the fruit compôte drizzled over the top.