I phoned them up this morning,half expecting a recorded message and half expecting a totally unhelpful experience. However they were quite helpful. I've found out that a reminder has been sent to Mrs Accy ,with them thinking i still lived there,reminding me/her to fill in the form online. They've accepted that she hasn't contacted me about the reminder and therefore i haven't filled in an online form. So i have to go and see them in town on Thursday where they'll fill it in for me. They haven't quite accepted my reason for not sending the form in,but they said they'd write telling what's happened and hopefully any charges will be dropped.
To cut it short. They thought i was still self employed. They thought i was still living with Mrs Accy. They've accepted it was a genuine oversight by me and not a case of me not being able to bother.