The key word in the quote is "secondary", IMHO.
This is the reason the solicitor / executor / personal representative requests PPSNs and details of beneficiaries, gifts received from for the testator and notifies Revenue in advance so tax liabilities and deductions can be calculated prior to disbursements being made.
IMHO, if it emerges that a beneficiary failed to notify Revenue of taxable gifts in tax years prior to taking out an inheritance, I can't see how the personal representative can have a tax liability (I'm not a lawyer / accountant).
If you can locate form "CA25.PDF", A Guide to completing the Inland Revenue Affidavit (Form C.A.24), on the Revenue web-site it is very helpful and informative.