1) There are non-EU foreign staff within the NHS.
Of course there are non-EU foreign staff in the NHS, but you have to jump through many more hoops to hire people from outside the EU (I've done it myself).
As an aside, I don't see why it is a good thing that the country relies on foreigners to run the NHS, we should be self-sufficient.
So, who's going to be the one to explain to staff that they should stay in the UK instead of moving elsewhere, if they have the opportunities to do so?
2) Ditto teachers / lecturers.
You are aware that the job of a lecturer is very different from that of a teacher? As a lecturer, particularly at research intensive universities, much of the emphasis is on your ability to conduct world-leading research. Whilst academic staff can also come from outside the EU, the ease with which staff can move within the EU certainly makes hiring of exceptional staff from other countries much easier. The future of HE is very uncertain post-Brexit.
EU research grants. Where do they get the money from? - oh yes, it's our money in the first place
What ALL of it? No. Didn't think so.
As a personal anecdote, when I was still a young post-doc, I was hired on an EU grant to another country which gave me very good tax break as I was bringing skills into that country that they didn't have. The type of grant was there to encourage mobility within the EU for up-and-coming researchers. There are many opportunities like this for young academics, but UK universities are now being grey-listed out of EU grants for fear of weakening applications.
I've visited non-EU counties and not needed a visa. It seems a bit silly to base the country's economy on a decision as trivial as whether I need a visa or not.
You can't assume you won't need visas to travel. You also can't assume that just because you would appear to travel only for leisure that this is true of the rest of the country too. It seems a bit silly to base the country's economy on potentially restricted movement.
5) Why is supporting the ageing a young person's game. We are all working until 67 or older these days so there are more man hours available.
Many of the baby boomer generation (born in the post WWII era) have had the luxury of retiring much earlier than 67. Do you think it is a good thing to force people to work until later and later into their old age?
These were just a few examples of how EU membership has benefited individuals even if they don't realise it.
It has really diminished some people's world view
That is funny.