Checking form IHT 30: section F
You should check the other guidance available on GOV.UK from HMRC as Brexit updates to those pages are being prioritised before manuals.
Section F is used when the application is accompanied by details of amendments that result in a repayment of tax (IHTM31601). There is space for applicants to give the names of the persons they would like the repayment to be made out to. This replaces any earlier repayment advice you may have received.
If Section F has not been filled in and there is no earlier information about repayments you should not reject or return form IHT30. If a repayment is due you should consider sending a form Sect 66a (IHTM31662).