1. To make the berry sauce, place the frozen berries in a medium sized saucepan and heat for a few minutes until they soften, crushing them with the fork or spoon.
2. Add the grated lemon rind, sugar and water and cook for a further 5 minutes its thickened and reduced.
3. Set aside and cool.
4. To assemble, first whisk the cream cheese until soft and smooth in a mixing dish.
5. Add the fruit yoghurt a little at a time, beating well after each addition to prevent any lumps from forming. Continue until all the yoghurt is mixed in with the cream cheese.
6. In a deep trifle dish start with a layer of the Swiss roll slices.
7. Top with custard. Next add the yoghurt and cream cheese mix and drizzle the berry sauce around the edge, followed by a layer of sliced strawberries and raspberries.
8. Next repeat the layering with swiss roll, custard, the yoghurt and cream cheese mix then berry sauce and fresh mixed berries.
9. Repeat the layering for the last time ending with the strawberries and finally a drizzle of the berries sauce.
10. Garnish with fresh mint. Serve immediately or cover with cling film and keep in fridge until needed.