Put the Swiss roll in a little bowl. Sprinkle on 4tbsp presse or juice. Add most of the strawberries.
Break the jelly up and put in a measuring jug. Make up to 300ml with boiling water. Stir until dissolved. Add the rest of the presse or juice and make up to 550ml with ice cubes. Stir until dissolved and pour over the trifle base. Chill until set.
Put the yolks, sugar and custard powder in a bowl and whisk until smooth. Heat 300ml cream and the milk until very hot but not boiling. Pour on to the egg mixture, whisking. Return to the pan and cook over a very low heat, stirring all the time, until it thickens - don't boil. Stir in the vanilla. Pour in a bowl, cover the surface with clingfilm and leave to cool.
Once cooled, spread it on top of the jelly and chill. Whip the remaining cream and spread on. Decorate with the nuts and berries.