Yes - if you've taken reasonable steps and we find that your sum insured is low at the time of making a claim, we'll choose to offer replacement cover if the damage hasn't been caused by natural disaster.
It's important to note that taking reasonable steps to calculate and provide an accurate home sum insured is a condition that must be met before replacement cover will apply. If you don't take reasonable steps to provide this, you'll only have cover up to the limit of the sum insured amount listed on your policy schedule.
You can find the full details of how we'll cover you in your policy document, under the section 'How we will settle your claim'.