Thanks :)
I ran this yesterday with second and third graders and my conclusion is that it's probably higher level than i initially thought. (Third managed with it, somewhat, but second struggled).
I'm gonna revise it, reduce the number of questions and add a picture round of famous cockneys when I get a moment (this will probably be a liberal interpretation of the actual definition of cockney, as my students didn't seem to know that many when I asked - Ron Weasley, 베컴, and Alfred from Batman being likely candidates).