LV, who i'm currently insured with, want £34 extra to cover a truck only till my policy expires in September. My current policy is circa £300, so quite good I think. However, they don't know what a demountable is, so their underwriters won't commit to providing insurance for the camper. However, my enquiry looks to have set some wheels in motion and they're looking into the demountable to see if it's a market they might offer a policy on. I've asked them to keep me appraised of any progress.
Camptons, cheapest so far for covering both with 10k miles at £450, so looking likely, but will need to add their recovery/breakdown to this total.
Awaiting a call back from Adrian Flux...
NFU!!! Just for the truck, £850

Once AF have rung back, i'm going to give C&CC a ring for camper only and Crusader a shout as well.
More later folks.