how will ANPR show the nationality of people crossing the border?
There is no requirement for that.

How will ANPR work out if any goods being transported are subject to duties?

That is not a problem. The current situation is that no checks are made for duty or tax payable now.

Why should a single penny be spent on infrastructure before 100% of the austerity cuts to Ealing have been reversed?

28 governments think it necessary.

If the leavers want to pay for it out of their own pockets that would be more acceptable.

We don't.

If there is going to be an open borde between NI and the EU there must also be an open border betwwen the rest of UK

The EU report say the border they envisage can indeed be scaled up for that purpose.
Depending on the trade terms, no borders may be required anyway, but so far EU refuse to discuss the trade terms.