INTM330340 | Double Taxation applications and claims: signature of declarations: Who should sign the declaration - deceased persons
From HM Revenue & Customs · International Manual
The personal representative(s) of the deceased person should sign claims made in connection with income received up to the date of death.
If you have not received a copy of the Grant of Probate or Grant of Letters of Administration or the local equivalent you may need to obtain confirmation of the signatory’s status.
You can obtain a copy of the relevant document by issuing a questionnaire 4442 but remember that you will have to open an SA enquiry, see INTM331200.
Guidance about income received before death is at INTM340040.
Where the income arose after the date of death
for claims by the personal representative(s) see INTM340050
for claims by beneficiaries of a UK estate see INTM367510.
for claims by beneficiaries of a foreign estate see INTM367550.