You used to be able to get just fire and theft insurance for stuff that is off the road. Can't give tou the names of any specific companies as it is a long time ago since I had such a policy.
Doubt you will find it offered online so you might have to call round a few places.
I don't think you will save a a fortune if you are only paying £200 now if you are not going to be off the road for a full 12 months it might not be worth the hassle, especially if it means you have to change mid policy period you could get whacked with charges for the change.
You might miss the opportunity to get some early spring rides in if you need to sort your insurance before getting back on the road.
There can be options to suspend your insurance but that might leave you with no cover rather than reduced cover.