I have confused myself, and know that I am overlooking something obvious, but:
Following a joint LA / DWP fraud investiation, DWP cancel back a Widows Pension some years creating an overpayment of DWP benefits of £20 000. If the LA removes this income back (in line with the DWP cancellation), this will create an HB underpayment of £10 000. Should the LA remove the DWP benefit back for the same period that the DWP removed it, or simply from the date of the new DWP decision? If the LA should create the HB underpayment, is there any way of setting it off against the DWP overpayment?