Just some additional info:
It looked like it worked fine, until we added a new product and noticed that the price changed. (This only applied for the new products, the old products were not affected.)
That is, if I was not logged in (front end) it displayed the price without vat tax.
And if I logged in (front end) the price was right, with vat tax (and also specifying the tax).
See image price.jpg.
Then we removed the shopper group we had added (see image mva1.jpg which I added in a previous post). And that did it.
Just thought this info might be useful for others like me... (who needs help sometimes)

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