IHT 400: Deceased’s Will (page 3).
If the deceased left a Will the question at box 24 will be answered ‘Yes’ . They should send a copy of the Will, any codicils and any Instrument of Variation if it alters the amount of tax payable on the estate. If any of these documents are missing and you need to see them you should write out to the people who submitted the account, asking for copies. You can also get a copy of the Will by filling in form Cap9 (IHTM09310).
Questions 25 and 26 ask about the deceased’s address at the time the Will was written, and whether it was disposed of before they died. This is to help identify whether the deceased may have made any gifts (IHTM14001) either of the property or the proceeds of sale from it.