I got fed up ringing “specialists” all of whom took an age to record the van spec and then get back to me, “or had to check that with the underwriters”.
A mate recommended Aviva who have been excellent. They’re the insurers so everything goes direct, they didn’t bat an eyelid at any of the modifications to my T5 (Alloys, body kit, tints, kombi conversion, interior, etc). Adding work use was a no-cost extra and all my docs are available online when I need them. Even better they were cheaper than the cost of my normal car the van replaced. They were also happy to mirror my no-claims while I took a few months to sell my car.
I’ve heard too many stories about Adrian Flux when in the modified car scene to even consider calling them up.