Income Support Overpayment

My client is single with 2 kids under 5. She has 4 IS overpayments:
15/09/06 -16/08/07 - £1330.22 client was in receipt of SMP;
17/08/07 -17/01/08 - £1301.30 client was working 16 hours p/w;
18/01/08 - 16/10/08 - £2270 .70 client was on receipt of SMP;
24/04/09 - 23/09/09 - £1405.42 client was working 16 hours p/w.
The appeal is listed for26/06/2012. The overpayments are correct. Client has been interviewed under caution, but no criminal charges threatened as yet.
Although I cannot challenge the overpayments, can I request an “offset” as client would have been entitled to WTC for some of the overpayments?
I would appreciate any advice at all!

There’s no mandatory offset under regulations but you can request they use their discretion if there would have been no (or less) loss to the public purse.  Only underpayments of the same benefit that has been overpaid must be offset, or underpayments of tax credits against overpayments of tax credits (reg 13 of the Social Security (Payments on account, Overpayments and Recovery) Regulations 1988).

edited to insert missing word

My reading is that The Decision Maker can only offset from an overpayment of income support, any entitlement to income support that a claimant would have been entitled to had the correct facts been known.  There is no power under regs, to offset any entitlement from another benefit (e.g. WTC).  (Reg.13 SS (PAOR) Regs 1988, see also p.1074, CPAG).... Unless poss for use of discretion as Nevip suggests.

Thank you both. It is a slim chance, but certainly worth a go.

I will certainly do this if DWP decide to prosecute.