I don't have a lot of knowledge on the subject but as I understand the NHS haven't used padded cells for quite a few years now. You obviously know more than me. I did read a report some time ago where they were being used in a school in Wales ... quite recently ... google it.Padded cells can be found in the majority of every medium or high security psychiatric unit in the country. They are used of course for patient safety when drugs alone do not work, and only used for a limited period for the patient to calm down.
Obviously you have great knowledge on the subject, so I stand to be corrected.