I'm re-reading the whole Swallows and Amazons series and decided I'd do it properly, so this is the very first time I read Coot Club and The Big Six. I'm delighted to say I really enjoyed them. The books set away from the lake are, for some reason, very much more class-conscious than the books set at the lake and The Big Six maybe most of all - money and class are very influential in this book. The Death and Glories come in for scrutiny the Swallows never would. It's notable that even though Tom was the Coot known to have unmoored a boat previously, he never really comes in for much suspicion; it's the Death and Glories who get particular scrutiny for theft and hooliganism even though they clearly aren't. Their dads nearly lose their jobs. It's not overly dwelt on but it's tremendously interesting. 

I will say, going to Missee Lee after The Big Six was awful and I nearly didn't make it through. Missee Lee is okay read around Peter Duck but it is horribly out of context this late in the series, coming after the we-all-nearly-drowned-in-the-North-Sea,  we-meticulously-mapped-some-tidal-islands, and we-were-framed-for-theft-and-it-nearly-worked books.