Hi Steve,
My S Type is the first car I have had wth an electrically heated windscreen.
On my 1962 Triumph Herald a demister was an optional extra and not fitted, and so a cloth and the quarter light open was the only way to keep the windscreen clear when driving. Car heaters were also optional extras, and a warm coat, scarf, gloves and cap were necessary in the winter. I still use my 1964 model Sheepskin Jacket!
Regards,
Peter.