Sorry, seems like the offer is over. When I ordered it on wednesday they were doing double cashback. Nokia seem to have voucher codes relatively often as well as the cashback, some people got 30% off a month or two ago I think, so perhaps they will have some more offers after christmas? I'd keep an eye on quidco/topcashback/hotukdeals if you want to wait till it's cheaper.

EDIT: Incredibly annoyingly I've just found http://www.hotukdeals.com/item/55714...-nokia-shop-uk for a 15% discount. Get that with 10% from quidco. Note that quidco specifically says that it might reject you if you use a voucher code in combination with it. That's what I'm going to tell myself anyway