Decided today to not go with the cheapest insurance quote, went with Caravan Guard instead, still £330 cheaper than last years insurer's renewal quote. Reason I chose them is that last year the policy documentation JustKampers sent me identified my van as a VW T6 campervan. No record of the specifics of the campervan build. Likewise Howdens and other companies I have been getting quotes from just identified a VW T6, or T6 campervan. Caravan Guard had a form which allowed me to specify that the vehicle in question is a VW-based Leisuredrive Vivante, and I feel a lot more comfortable with them being completely aware of exactly what they are insuring.
No mention on the form about demanding a tracker fitment, just a yes/no question as to whether the van has one.