You can get insurance from Direct Line for Business that covers 'home business' and this applies whether your office is in the house or in the garden.

In terms of an address, you can still use your residential address if the business is operating from the shed.

Be careful of planning permission. If you're operating quietly within the shed, you'll be fine but excess traffic to the house/loud noises etc may mean the nature of the shed changes from a 'shed' to a 'business premises' and your Local Authority may start asking questions.

But in terms of address/insurance, you're fine for the shed to be considered your home office location.

Emma