There are people on The Guardian's staff who know full well what is wrong with this article: Jack Schofield, Aleks Krotoski and Bobbie Johnson are three that immediately spring to mind. However, they didn't get to see it before it was published. The author didn't notice anything odd, though, and neither the sub-editor.
Doing a little investigation, it appears that the source is a Reuters report that makes the same mistake. The reporter read some court documents (which don't make the mistake), which he misinterpreted because he's programming-illiterate. Basically, he didn't know the difference between code and code.
I've never come across a programmer who pluralised the word code when referring to that which is written in a programming language, and I don't suppose I ever will.