Put the digestive biscuits in a bag and bash with a rolling pin or alternatively place in a blender on a low setting. Place in large mixing bowl and set aside for now.
Slice each of the marshmallows into 4 ( or 2 - depending on how big you want them to be)
Slice the glace cherries in 2.
Place half the marshmallows and cherries into the mixing bowl with the biscuits and pour in 150ml of condensed milk. Give it a good mix and add the rest of the marshmallows and cherries. If the mixture looks like it's on the dry side, add a little more of the milk.
Cut a large piece of clingfilm (or tinfoil) and put half of the coconut on the clingfilm, then pour the mixture onto it. Put the rest of the coconut on top and roll the clingfilm over to create a sausage shape.
Chill in the fridge for a couple of hours to harden.
Once chilled, cut into 15 slices and enjoy!