Do I need to fill in an IHT400 to claim unused allowance and unused residence relief

I am dealing with my wife's estate. The estate is left to her 2 daughters and includes a house that my wife used to live in. She has unused allowance and unused residence relief following the death of a previous husband, which together with her own allowances add up to £1m. The net value of the estate is about £850,000 . When I look at the Probate form, I find that Section 7.4 asks If I am claiming unused nil rate band of a pre-deceased spouse but the Note to 7.4 says "Only answer this question if the net qualifying value of the estate is between £325k and £650k" Do I have to complete an IHT400 form even though there will be no IHT to pay?

Hi,

Please contact the Inheritance Tax team for advice:

Inheritance Tax: general enquiries

Thank you.