My auto 1300 mk1 always tends to sit about half. Took these couple on the way down and back from SFS in Melb a couple of years back.

And 40 degrees bombing down the freeway it hot a little hotter.
I did buy a new temp sender at one point, from Repco I think it was, and maybe a green coloured one, can't remember. But it would only just move the gauge off the bottom. Wasn't happy with that so found another white (I think) one from a spare engine and put that in and all was the same again.