They are doing their job (at last) making sure healthcare tourists get billed

NHS hospital treatment in England

If you move to the UK, you will not be charged for NHS hospital treatment from the date that you arrive as long as:

you intend to live permanently in the UK, and
you have the right to live permanently in the UK or have a "route to settlement" that will allow permanent residence in due course
http://www.nhs.uk/chq/pages/1087.asp...categoryid=162