If the house is in joint names then this would NOT be a good move - the house would be at risk as the debt would be levied against any capital in the house.
I'm pretty sure - actually certain - that store cards are unsecured loans.
@cyberknight I would definitely NOT touch your pension.
When your wife (not you!) goes to the relevant places that help people in debt, she will be suggested several options, one of them is to go bankrupt.
You are you, she is her, we are in modern Britain, no way you can be held responsible for debts that are not in your name - unless you co-signed the credit agreements, which I don't think you did as you didn't know about the store card debts.
Imo, let her sort it out herself.
Yes, lots of menacing letters will arrive at your address, but, as you said, your wife does not earn enough to repay the loans.
Nothing is going to happen apart from her being blacklisted.
Of course, you could also go to your wife's debt crisis meetings, but don't offer to pay anything!