Thanks for all the useful help so far!! Please keep it coming. I'm especially looking for courts martial that have a lot of controversy - I guess the First World War is a gold mine in that respect - but also ones which resulted in a change in the court martial system.
As for Breaker Morant. I'm afraid it is a true story, though quite how much "artistic licence" was involved I am not sure.
I found an amusing case, which unfortunately not quite what I'm after, where an army soldier drank twenty pints, went back to a friend's house, ironed his hamster and then put it in the microwave to 'warm him up a bit'!! The article (from the BBC website) says that 'he was also charged with desertion'!
The research continues.....