Wrong Gross and Net figures in grant

A client has submitted a personal application and submitted the application and the gross figure for the estate is incorrect, by £25,000. The estate is substantially less than the IHT value - do they need to inform the probate registry and have the grant updated

I believe that the answer is no. However, was an IHT 400 submitted? If it was then, obviously HMRC will need to be informed as presumably tax has been paid which should not have been the case.

Patrick Moroney