I'm an idiot. I was forwarding a spam text to 7726 and the phone said something along the lines of 'this might cost money'. Then, via some not paying attention of fingers, I pressed something that has blocked sending of certain kinds of texts, I assume to prevent premium rate texts being abused. However, it means I can't forward on spam messages to O2, can't get certain settings and so on ... I can't find a way of undoing what I did - there's nothing in the message settings, and can't even find anything online about this 'wonderful' blocking of premium texts feature. Help, please!