How secure are AlKo Secure Wheel Locks?

My caravan, fitted with an AlKo Hitchlock, a pair of Winter Wheels Axle stands c/w locked covers and secure wheel nuts, rear corner steady locks, a Fiamma Secure Door lock, and an alarm, has just been stolen. All the security devices were wrenched off the van and discarded where they fell and the alarm was ripped out of the van and buried in an adjacent field ( presumably to silence it!! ). I intend to continue caravanning but am now wondering how I will secure it. It will come fitted with an AlKo Secure Wheel Lock - has anyone any knowledge of a van being stolen whilst this has been fitted? Should I have one fitted to each wheel? What else can I do ? Help!!