Just to clarify matters - The NHS in the UK is funded through Taxation and National Insurance Contributions paid by everyone who works or is self employed.
When I started work back in 1968 you actually paid a "Stamp" weekly from your wages and it was literally that - a stamp which was affixed to your NI card weekly - hence the expression when you left a job - "Collect your Cards."
That said, I have lived through Labour Party and Tory Party Governments - and both were prone to amalgamating anything paid from Taxation into the "Consolidated Fund" from which both raided to fund their Pet Projects - usually not mentioned in their Manifestos prior to elections.
Vaping I am sure will end up taxed as smoking was, and funds raised will not be "Ring Fenced" for the NHS.
As an example I offer - many people believe the "Road Tax" fund is ring fenced to repair the roads - it isn't - it is now "Vehicle Exise Duty" and all monies raised thereby go into the Consolidated Fund which the Government of the day uses to spend on what it will.
The NHS is NOT funded by Government, which per se has no money, it is funded by Tax payers. There is no such thing as a Free Lunch.