Did the United Kingdom ban an ad poster for being offensive to Christians?

Image showed singer lying on crucifix-shaped mattress

Demi Lovato performing in 2012. Publicity photo released under CC BY 2.0 license.

One surefire way to get free publicity for your artistic endeavors is to have your work banned somewhere, and that appeared to happen this week as headlines in both traditional and tabloid news media said that a Demi Lovato advertising poster had been banned in the United K…