Lightly grease a 23cm/9inch loose-bottomed round cake tin. Cut a strip of non-stick baking parchment to fit around the sides of the tin, fold the bottom edge of the strip up by about 2.5cm/1inch creasing it firmly, then open out the fold and cut slanting lines into this narrow strip at intervals. Fit this into the greased tin with the snipped edge in the base of the tin and put a circle of non-stick baking parchment on top.
Preheat the oven to 160C/325F/Gas 3.
Put the digestive biscuits into a polythene bag and crush the biscuits with a rolling pin. Melt the butter in a medium pan; add the crushed biscuits and demerara sugar.
Mix well, spread over the base of the tin and press firmly with the back of a metal spoon. Leave in a cool place to set whilst mixing the cheesecake.
For the cheesecake, measure the butter, sugar, cheese, flour, lemon rind and juice and egg yolks into a large bowl and beat well until smooth.
Fold the lightly whipped double cream into the mixture using a plastic spatula or large metal spoon.
Whisk the egg whites with a hand held electric mixer until stiff but not dry and fold into the mixture.
Pour on to the biscuit base and gently level the surface with a plastic spatula.
Bake in the preheated oven for about 1/1¼ hours or until set.
Turn off the oven and leave the cheesecake inside for a further one hour to cool.
Run a small palette knife around the edge of the tin to loosen the cheesecake then push the base up through the cake tin.
Remove the side paper and put the cheesecake on to a serving plate.
Spread the lightly whipped cream in the dip of the cheesecake and scatter the fruits haphazardly on top. Lightly dust with icing sugar if wished.