Place a piece of sponge into the base of the loaf tin, using the remaining piece to fill any gaps. Pour over 1/3 of the cooled coffee mixture. Spoon over 1/3 of the custard mix, spreading it to cover the sponge. Top with another piece of sponge cake and another 1/3 of the coffee and custard mix. Repeat the layers, smoothing out the fil custard layer on the sponge cake. Cover with cling film and refrigerate for 4 hours or overnight.