Can I just point out that, contrary to the assertions by some commentators, DAESH (it's an acronym and should therefore be capitalised) is not the great insult to IS? In fact, they embrace the name, as it is similar to the Arabic 'dais', which means 'crush or trample'... which is what they're trying to do.
Using DAESH was suggested by the Americans, arising from an Internet meme, as a piece of psychological warfare that has backfired and has been adopted by some British politicians and commentators as they think it makes them look 'in touch' - whereas in reality it makes them look like plonkers.
Describing IS as the "so called Islamic State" will be more insulting than calling them DAESH.