Discovery 3 - detachable towbars are they safe?

Lindyloo

We are just in the process of purchasing a 2006 Discovery 3, but we need to get a towbar for it.  Are the detachable ones safe, or is it better to tow a caravan with a fixed one?  We have heard of some horror stories, but not sure whether these were down
to user error etc.  Our caravan is a 2007 Abbey GTS 418.