I was close to writing 'It's so typical to rate strong violence suitable for 15-agers and sexual stuff for 18-agers', until I saw you're English, not American... they infected you with a prushish mentality! :p (and yeah, I do think you miss the
35 rating in there!)
Anyway, I think it's a good idea to rate selfmade games for the public audience in order to prepare them for the contents
so noone loses their mental virginity before they recieve their pension payment for example. I think your badges do quite a good job, especially because of the explanations... I'd prefer a no-age-containing version, though, so you'd get something like the Austrian method of signing media stuff with: They have several badges like 'Drug Stuff', 'Sexual Content', 'Violence', 'Language', ..., and depending on the game, the needed things get attached along with a mark on the age suggestion for the game. Think about it, it'll only be a matter of minutes to pull this off either way :p
