I feel your pain, Dave ... I had similar problems when I told insurance companies that Snail was my "Sole" vehicle ... several would not even quote ... Insurance companies seem to be a law unto themselves ... I eventually got a good quote from Adrian Flux, which was funny because last year they quoted me a ridiculous price ... they are inconsistent and confusing and IMHO should be better regulated to stop the silliness ... but not holding my breath for that to happen
Hope you get sorted ... there is a page on Facebook if you are on there
https://en-gb.facebook.com/motorhomefulltime/ ... or google Motorhome full time ... there are forums that seem to specialise in fulltime