I have a MK 3 Carens and my gauge sits just under half way.My scangauge shows normal running temp to be 85/87 degrees but in traffic it can get up to 93/94 BUT the gauge does not show any difference.
They are relatively crude instruments and having done nearly 50,000 miles I would be worried if my gauge started rising above the middle.
My sons BMW also shows just about mid way after a long run so it seems to be fairly common with modern vehicles.
Don't worry about it!
M623D - yours seems a bit low, maybe the thermostat is stuck open?