The key stage 3 Literacy across the Curriculum folder (DfEE 2001b) provides a list of types of non-fiction writing and interestingly encourages teachers to provide pupils with an oral example of each type:

Instructions: recipes, giving directions.

Recount: science experiment write-up, match commentary

Explanation: the rain cycle, how erosion occurs.

Information: food in Britain, the properties of mercury

Persuasion: advertisement, manifesto.

Discursive writing: ‘discuss’ essays, magazine article.

Analysis: literary criticism, analytical essay.