What a great idea for a thread - I'll definitely look up some of these.

Our favourite series here is Enid Blyton's Famous Five - and if your children enjoy them there's plenty to keep them busy - I think there are over 20 in the series. And since they're 1940s-ish vintage definitely not a trace of toilet humour (told the boys only tonight that the police don't consider it murder if you strangle your children for continuous toilet jokes). Lots of villains, hidden dungeons, secret passages etc.