I've just purchased a motorhome cover for my van, it's the half cover so it don't cover all of the van, very pleased with it, the only thing that worries me is it covers the tax disk, the van is parked on the road, just wondering if I could get nicked for not displaying a valid tax disk?, I could always cut a little hole, but don't want to do this really.
Have you bought a windscreen and side windows cover?. Not sure what a half cover is....unless it covers the whole roof, and finishes somewhere around the middle of whole vehicle and not all the way to ground level?. If it is just windshield and side windows, are there any windows into which you can put the disc? It should as you know be in the front window. I would, IF other windows are available, write with a permanent marker where it can be found. UNLESS you know a good machinist who can 'oversew' any hole cut for viewing the disc. Best of luck mate...you know how many 'jobsworth' officials there are out there.
Theoretically you are failing to display an excise licence, but the DVLA data base will inform anyone who checks it has a road fund licence.insurance and MOT if kept on the road.
I doubt but you never know that the matter would ever reach the courts let alone the CPS