After some research, I found this tutorial for a Portal Cake by The Geeky Chef: http://www.geekychef.com/2010/09/delicious-and-moist-cake.html
As the recipe used US measurements and ingredients, one of the most time-consuming parts of the project was converting it into grams and finding UK versions of the ingredients featured, so I've put this tutorial together using ingredients that you can get from most UK supermarkets.
Although the cake itself is pretty ambitious this tutorial is suitable for complete newbies - I haven't baked in about 8 years and was figuring out most of the techniques used in the recipe from scratch, and have included tips on anything that went wrong.
A couple words of warning: this cake isn't exactly cheap - the cherry liquor alone was £8 and the recipe uses most of the bottle. You'll also need two free evenings (or an entire day) to complete it: one for the baking and one for decorating it after it cools.
Also, after baking one as a trial run I couldn't be bothered doing it all again for the actual bake off. I'll be posting another Instructable soon of the next cake I tried: a peach pie with laser cut icing.