No. You can take out your own insurance but it must cover goods being placed in self-storage.
Not all household insurances will cover you whilst your possessions are in a self-storage facility, so please check the terms of your insurance and provide us with proof of your cover if not using Surewise, which must state that it covers goods stored in a self-storage facility, and name the store you are storing at and the full postal address of the premises. It is your responsibility to keep your insurance documentation valid and up to date.