Do HB automatically know about changes to Tax Credit

One of my Cl’s children went to live elsewhere, cl notified CB and CTC, both of which reduced. They say that they also notified HB but amount did not reduce. When c of circs was uncovered it generated a considerable O/P of HB.

There is of course an arguable point that the cl. should have realised that HB should have gone down and checked with HB when it didn’t but aside from this does anyone know if the HB dept is automatically notified by Tax Creds of changes to the make -up of the household?

it may be that the local authority received an ATLAS showing a reduced amount of tax credits in payment, but that wouldn’t state the reason for the change, so no, the council wouldn’t be told about the changes to the household by tax credits.
She has a duty to tell HB about changes to her household and she didn’t, so think she’ll have a tough time if hoping to appeal the o/p
She contributed to it by not telling the local authority about her change

yes, the Council ***could have****  written to her saying ” there is a big change in your tax credits so please tell us whats changed in your circumstances” but that ‘s very good practice and not many authorities do it.