After much labour we have the 2S spell checking functionality back.
Just click the 'Spell Check' button beneath the post box to get some spell check suggestions.
It's using an en-US dictionary as en-GB ones are awkward to install... but it's almost as good. If you want to use a different language spell check then I recommend that you install a dictionary extension for Firefox or Google Chrome.
I hope you approve of spell checks return,
-2S Admin Team