Previously with ********* for insurance who demanded that wheel lock, hitch lock and alarm were all fitted, but were useless and took 6 months to pay out after caravan destroyed in storage compound fire.
Replacement caravan is now insured with caravan club insurance, we have to have only one security device, either hitchlock, wheel lock OR an alarm but with the addition of others you can reduce your premium by discounts. The cost of the device if you have to buy from new is more than what you will save in the short term.