I have replaced not only the gauge(actually the instrument cluster), but switched voltage regulators both of which make a difference. At this time the gauge shows in the high/normal range. It shows cooler when the weather is hot.
I presume that's because the water gets hotter and the thermostat opens wider.

Still not happy with high/normal, as I would rather have it in mid normal. But as the actual water temp in the radiator is not boiling, I am living with this for now.

Thanks for all the replies, and I am still working on this.

Rog