DVLA rejected my application to have my MP reclassified as a Motor Caravan despite it clearly meeting their published criteria at https://www.gov.uk/government/publications/registering-a-diy-caravan/converting-a-vehicle-into-a-motorhome. I have written to them contesting their decision. Researching the matter further, I came across this https://petition.parliament.uk/petitions/267623 . It seems DVLA have now decided that reclassification only applies if externally the vehicle looks like a motor home but it seems did not publish this change of policy. If they refuse again, I shall refer the matter via my MP to the Parliamentary Ombudsman.