Hi Dave
We've had a couple of Euroclamps - the standard one which was very easy to put on, and just as easy for the thief who stole our caravan to take off BUT I hadn't fitted locking wheelnuts. Lessons learned.
We now use a more expensive (and tougher) 'SS' model which has the Sold Secure silver rating needed by our insurers (Caravan Club). It's just as easy to put on, but generally stronger and we have also fitted locking wheelnuts (any caravan dealer sells them). To be honest, having had one 'van nicked we now use three wheelclamps in total - a Sold Secure Milenco and a cheap and nasty Klampit which is really just for show. The Euroclamp is ideal for short stops (at motorway services for example) as it really is a click and fit device. Best advice is NOT to use it with a wheel trim, but then with alloys you wouldn't anyway. In short, quick and easy to fit, but make sure you go for the SS model and also fit locking wheelnuts.