Unless specifically agreed to the contrary the provision of this clause shall only apply to the sums insured in force at the commencement of each period of insurance, and at each renewal date the insured shall notify the insurers of :
1.the sums to be insured under each item, but in the absence of such instructions the sums insured under the items shall be those stated in the policy (as amended by any endorsement effective prior to the aforesaid renewal date) to which shall be added the increase which have been granted under this clause during the period of insurance up to that renewal date, and
All the conditions of the Policy except insofar as they may have hereby been expressly varied shall remain the same.