Grease a slice tin (approx 27 x 17cm) and line with baking paper, leaving paper overhanging at sides to assist with removal of slice later.
Line bottom of tray with milk coffee biscuits, cutting to fit if necessary.
Add coconut, tin of condensed milk, halved glace cherries and 5-6 drops of red food colouring to a mixing bowl. Stir well to combine. Mixture should turn pink and hold together well.
Layer mixture on top of biscuits in tray, spreading evenly and pressing down with fingers to create an even layer. Smooth this layer with the back of a spoon.
Melt milk chocolate in a bowl using 20 second bursts in the microwave. Stir well between bursts.
Pour melted chocolate over top of coconut mixture, using a spoon or tilting tray so the chocolate evenly coats the top of the slice.
Melt dark chocolate in a bowl using 20 second bursts in the microwave. Stir well between bursts.
Drizzle dark chocolate over milk chocolate layer.
Place into fridge for at least 2 hours.
Remove tray from fridge and lift slice out of tray using edges of baking paper. Allow to sit for 20 minutes (to avoid chocolate cracking is you cut into slices) before cutting into squares with a sharp knife.
Store in fridge for up to one week.