In order to insure a house, you must have an insurable interest; that, in effect, means that you must have the rights of an owner. The executor of a will has those rights, but the position might be unclear in the interregnum between the date of death and the grant of probate.
Insurance companies generally do not like covering vacant properties, and that can be a further complication. There might be a presumption that the property is vacant unless you make it clear that you are occupying it.
I suggest that you fill in a proposal in your capacity as "Primrose as Executor of the will of ..." and state that you will be living in the house.