First off, I'm not sure why some people are lambasting this for not using home-made cake. Do you honestly buy a book like this for recipes? I could understand the annoyance if this book was for standard cakes or cupcakes, but these are neither, they're little novelties and as such I wouldn't expect a massive variety of recipes for it. In addition, if you are looking at this book I'd be willing to bet you have a pretty good understanding of baking, so knocking up your own cake shouldn't be an issue, especially since it states very clearly what size cake and what weight of frosting is required.
It is explained immediately that the author prefers the shop-bought mixes and frostings as a) they give standard quantities and b) it means she can get to her favourite bit, the designing, more quickly. Personally I don't like mixes so I would use my own recipes, although she does give one or two basic ones at the back of the book.
The designs themselves are very cute, and they are all explained in great detail. Despite the fact they look complex, I think these could be accomplished by anyone so please don't be put off if you're new to baking and decorating. The steps are explained from scratch on each design so you don't need to look back to the beginning for the basics which is a nice touch. I also really like the ideas she has for using sweeties like candy necklaces (robot eyes) and mini marshmallows (popcorn) - that really got my imagination running with ideas for how to create other things:)
Candy melts are available over here online - check the Wilton website for UK suppliers. Googling also brings up a few results. Failing that, use white chocolate (if you're confident with working with chocolate), or if you're not then just use white chocolate flavoured cake covering. Both can be coloured, although you must make sure you don't use water based colourings. Again, candy/chocolate colourings can be bought online or in cake decoration shops. Ebay now has a massive selection of things for the cake pop market too, and is normally a good source for the odd bits of American candy that you can't find here, such as candy corn (although I did think some of them looked very similar to our coke bottles/milkshake bottle sweets).
My one complaint, and it's a small one, is that the spiral binding is one of those that doesn't flow very well. It's only a minor niggle though and nothing that reflects poorly on the content, so this is still a five star book imo.