Grease the round cake tin (approx 20cm x 5cm).
Break biscuits into (roughly) almond size pieces by hand and set aside.
Cream butter and sugar.
Break chocolate for cake into pieces and place into a microwaveable bowl. Melt chocolate using 20 seconds bursts and stirring between each burst until completely melted.
Add melted chocolate, golden syrup and thickened cream to butter mixture and beat on medium speed until well combined.
Pour chocolate mixture over biscuits and stir until biscuits are completely coated in chocolate mixture.
Spoon mixture into cake tin, ensuring your press mixture gently into the edges of the tin and then smooth top with back of a dessert spoon.
Chill for at least 3 hours.
Remove cake from tin, using a butter knife if necessary to ease cake from the sides of the tin, and invert on a wire cooling tray. Place baking paper under the tray.
Break chocolate for icing into pieces and place into a microwaveable bowl. Melt chocolate using 20 seconds bursts and stirring between each burst until completely melted.
Pour melted chocolate over the cake and use a spatula to smooth over the top and sides.
Place in fridge and chill again for at least 5 hours.
Decorate with edible flowers just before serving.
Sit at room temperature for 10-20 minutes before cutting into slices.