Not sure if this is nationwide but they have signs up in Cardiff IKEA saying their sale starts 18th December.
Shared Via The HUKD App For Android.
It is nationwide starting from 18 December and instore only!
Also 12 months interest free Credit
When you spend £400 or more on sofa, sofa-beds, armchair or footstools, (The interest free credit is for limited time only, until 31 December)