CLT - trustees decide to pay IHT instead of settlor (after IHT100a submitted)

An IHT100a is submitted to HMRC, with the settlor paying the IHT (with grossing up). The settlor and trustees later agree that the trustees will pay the IHT, from the trust funds (with no grossing up). The IHT is not due until October.

We informed HMRC by letter and asked if they need (i) written confirmation from the settlor or trustees; (ii) a revised IHT100a; or (iii) a new IHT reference, instead of the the settlor one already issued. Their reply is that it is being “referred to technical”.

Long gone are the days when a call to the Capital Taxes Office would provide a quick helpful answer.

If anyone has experienced this situation and is able to answer the question before HMRC do, that would be much appreciated.