Put all the biscuits in the Ziplock bag and smash them up by bashing them with the rolling pin. Until they resemble crumbs but dont worry if you have the odd larger lump.
Melt butter in saucepan, stirring to ensure it doesnt burn. Once it is liquid take it off the heat and pour the biscuits crumbs into the butter
Stir until completely combined
Add half the biscuit mixture to the bottom of the bowl and press down to ensure it is covering the whole base, and if you can, push it slightly up the edges too
If you want a proper (traditional trifle) you can skip all of this stage and just use slices of ready made cake. We didnt have any so I used biscuits.
Open two of the caramel tins and carefully smooth it over the biscuit base until it is covering, and is flat
Add one of the custard cartons on top of the caramel and smooth into a single layer
Slice three of the bananas and lay them out in a single layer on top of the custard
Repeat those three layers, biscuit (or cake), caramel, custard, bananas.
Whip the cream until it is thick and spoon on to the top of the bananas, ensuring all the bananas are covered so they dont go brown before you serve.
Sprinkle the chocolate chips on top