Hi Quintus
I am not aware of any rule changes, if there were any then they would be published in one of our news letters.
I would contact the DWP and find out why they sent you the letter and at the same time inform them that you do not have any Private Health Insurance.
Let us know how you get on, the best time to phone them is first thing in the morning, 8.00 am.
Gary
Nothing on this board constitutes legal advice - always consult a professional about specific problems