here's one thast contains cool whip....its like dream topping so should work in the uk (can you still get dream topping?)
http://frugalupstate.blogspot.com/2009/01/coff ee-mousse-recipe.html
My Dad used to make one by mixing instant coffee, sugar and gelatine then folding it into stiffly whipped evapourated milk then leaving to set in the fridge, but I don't have a recipe as such. I do know that you need to have the evap. very cold (straight out of the fridge) for it to whip and its way easier with an electric whisk