Spell checker option
 

It would be nice if I had the option to switch off the spell checker for some documents. The need for this may not seem obvious but there are circumstances where a spell checker is not desirable, for instance if your document is a chunk of source code where all the windows calls and variable names become highlighted as being mis-spelled.

Alt+T, Q, Enter, or customize the toolbar and add that command.
http://kinook.com/UltraRecall/Manual...ovebuttons.htm

Maybe I'm being stupid here but I don't see anything which would allow me to switch off the spell checking for individual documents, just an option to switch off the spell checking completely.

No, there isn't. I was just showing a quick way to switch it on and off.