IHT 100: Section C - Person we should contact
This section gives you the name, address, telephone number and reference for the person, bank or firm of solicitors that is dealing with the transfer.
There is detailed guidance on confidentiality (IHTM02031). But the general rule is that you should only discuss the transfer with those who signed the account or someone who has been appointed to act for them, usually a firm of solicitors. You should assume that you have the authority to deal with this person or firm until those who signed the account tell you otherwise.