Vonsworld

We have an estate which is worth £450,000 and would like to claim the Residence Nil Rate Band. This means the threshold is raised to £500k and there will be no IHT to pay. Therefore is this regarded as an excepted estate and can we just enter the values on our online probate application? Or do we still have to make a full return to HMRC using firms iht400 and iht435? Thanks