I think you will find the most you are going get is 6 months and not lower, unlike Holland (unless they have changed) you could effectively tax your vehicle for just the weekend or for a day ie. buying and driving it home.
Dayinsure cover for up to 28days. If you own the motorhome & keep it all year you still need insurance all yr for fire & theft etc though even if you only drive it for 1 month a year.
Amazing family weekend with old steam engines, classic car displays, market stalls, and full catering and bar. And camping on site - Save £25 by booking in advance.