Hi All
I'm really sorry, I forgot to check this post but good things come to those who wait 
Sorry it's in old money but you could convert it to grams.
Here is the recipe:
For the Base:
Tin 11" x 7" (a little smaller will be fine but any bigger and the base might get a bit thin)
7oz Rich Tea biscuits
4oz Marg/Butter
4oz soft brown sugar
2 tablespoons of Ovaltine (original kind where you add milk not the low fat)
3oz Dessicated coconut
1 egg (beaten)
Crush the biscuits (I use the end of a rolling pin in a bowl to get a good range of different sized pieces)
Melt the butter, sugar and Ovaltine in a saucepan and stir until melted together.
Add the coconut and mix well.
Take off the heat and allow to cool for about 2 minutes before adding the beaten egg, stir constantly and return to the heat until it bubbles (keeps stirring to make sure when the egg cooks from the heat it is mixed in)
Take off the heat and mix in the biscuits.
Spread the mixture with the back of a spoon into the tin.
For the Topping:
14oz icing sugar
3oz margerine (you could use butter)
3 tablespoons custard powder
3 tablespoons boiling water.
Cream together the marg, icing sugar, custard powder and water with an electric whisk, it should be fairly stiff.
Spread over the biscuit base and sprinkle a little Ovaltine powder on top.
Place in the fridge for a few hours to set.
Let me know how you get on and what you think.