This is exactly what I have read and believe as well.There's many different stories about this. The one eye favour came from LR. Post war steel was rationed. They got all they could and wanted it for use buildering rover cars. Aluminium was more easily available so they used that.
There's a lot of myths like tratters being built as a stop gap when post war sales of rover cars was low. The time and effort to get tratter production going couldn't justify only a few years production. But the myths will continue.
Sales were not low, people were screaming for cars but they were not allowed to sell to the home market, they i.e. the govt, needed exports to help the economy. The phrase they used at the time was "Export or die" so they sold loads of cars to the USA and fortunately they devolped a real liking for Brit sports car particularly.
Still a shame that some journo put this out unedited.