I think you need to see the small print of the agreement from 2010 on how the replacement system will work.
Since the event of Trusts and Foundation Trusts in the UK, hospitals act like independant businesses and recover costs from primary care trusts for treatment afforded to patients by use of their permenant address post code.
It maybe that the Isle of Man as it has a national health service would be joining in this system instead of having a carte blanc lump sum payment arrangement.
If so the changes to an Isle of Man resident or a UK tourist visitor would not be noticed.