As a minimum we require a wheel clamp and hitchlock to be fitted when the caravan is left unattended and detached from the tow vehicle. Of course you wouldn’t need to fit this security when you were just stopping at a motorway services.
An axle wheel lock is accepted in lieu of a wheel clamp.
For some higher risk caravans we may require additional security such as axle wheel locks, alarms or Happy Place approved tracking devices.