I don't think it as straightforward as that David. It not only depends on the insurer, but also where you live and what you are storing (and it's value) in the shed.
If you mean you are storing your tackle in the shed, I would advise against it as many insurers won't cover it or impose a high excess. Store your rods and reels in the house and leave the rest in the shed.
All I can really suggest is ringing around!
