I wonder if it would be appropriate to "dramatically overreact" and send in the SAS or similar to send a polite message that mucking with the NHS is really not a good idea.
Maybe post offer a decent reward - say £10 million for information leading to the identification of the culprits.
Labour won't attack on this because they know it might have happened to them just as easily, whereas it fits the Tory narrative that "the NHS is useless and should be privatised" with almost no spin.
Most of my local Tories know that any kind of direct assault on the NHS would result in instant annihilation at the next election.
There are more subtle methods of course including outrageously broken internal market management restructures (Stafford Hospital Trust, 'fund holding GPs' in the time of Thatcher) and the like.
I suspect that if this does happen it will more likely be the French retaliating against the hacking of the election the French version of SAS/DELTA don't fuck about.
Maybe post offer a decent reward - say £10 million for information leading to the identification of the culprits.