Not me.
Before doing anything, I would ask Direct Line for a list of approved devices.
Otherwise you may fit one, and they still won't insure your campervan.
They are many trackers to choose from.
Real time trackers, activate after theft, etc.
Your car will have a immobiliser, and cannot be towed.
My advice ? Depends on the value of your camper, but I would shop elsewhere.
I went with Scenic, part of LV, but, my guess is the value of your van will exceed their upper limit.
There is a list of Insurers on a thread in this Forum, but not all will insure conversions.
Persevere, and Good luck