Place the Swiss roll slices at the bottom of the trifle dish and use any leftover cake bits to fill up the bottom layer.
Add some of the speckled eggs, marshmallow Easter eggs, and hot cross buns at the bottom. You can decide how much to use—just keep some aside for another layer.
Prepare the instant chocolate pudding according to the packet instructions and spread it over the hot cross bun and Easter egg layer.
Whip the cream until stiff and spread half of it over the chocolate pudding layer.
Add another layer of hot cross buns, Easter eggs, and speckled eggs on top of the cream.
Now spread the chocolate mousse evenly over that layer.
Top with the remaining whipped cream and smooth out.
Sprinkle with chocolate shavings, place the chocolate bunny, and decorate further with Easter eggs.