Good morning.
Try Footman James 'laid up cover' They say this:
'This valuable cover applies whilst your vehicle, its accessories and its spare parts are kept in a locked garage/building. Your classic motorcycle is also covered while it is temporarily out of the garage if you are exhibiting it, or having it repaired, in the UK (including while it is transported by trailer to and from the exhibition or repairers premises). Agreed Value option available on Laid Up policies'
Other providers are available
R