Make the cheesecake. Lightly grease the base and sides of a 20.5cm (8in) round springform tin. Unclip the tin to remove the base, then take a 30.5cm (12in) sheet of baking parchment and lay it over the base of the tin. Carefully clip the paper-covered base back into the tin so the paper is tightly stretched over the base and any overhang is pulled underneath the join, then line sides of tin with another piece of baking parchment.
Whiz the biscuits in a food processor until they are finely crushed - alternatively, crush them with a rolling pin. Add 125g (4oz) of the melted butter to the processor or bowl and pulse/mix until the mixture clumps together. Press firmly into the base of the prepared tin using the back of a spoon and chill until needed.
In a large bowl, beat the cream cheese, icing sugar, Pimm's, remaining melted butter and lemon juice together with an electric handwhisk until smooth. Fold in the citrus zests and mint.
In a separate bowl, whip the cream until it just holds its shape, then gently fold it into the cream cheese bowl until combined.
Tip the cheesecake mixture into the tin and spread to make an even layer. Chill in the fridge for at least 6hr or overnight.
Meanwhile, make the Pimm's syrup. Put the Pimm's and sugar in a small pan, heat gently, stirring to dissolve, then bring to the boil and bubble for 4-5min or until the mixture is syrupy. Remove from the heat. Whisk in the strawberry jam. Add the strips of zest, mint leaves and cucumber and swirl the pan. Leave to infuse and cool completely (at least 1hr), then strain into a small jug, cover and leave at room temperature.
Remove cheesecake from tin and transfer on to a serving plate or cake stand. Peel off parchment paper around sides. Drizzle some of the syrup over the cheesecake. Arrange the strawberries, orange slices and cucumber on to the top of the cheesecake, scatter over the mint leaves. Serve in slices with extra syrup poured over.