maybe the reason Brits & Aussies (and others) drive on the left of the road??
This goes back to the days before automobiles, when people travelled on horseback and when passing they preferred to keep each other on the side which they would present their sword for defence. Not sure why the rest of europe do it the other way, as far as I know they are not all predominantly left handed!
Countries driving on the left:
Japan, UK, Ireland, India, Australia, NZ plus a few more.
Sweden changed overnight on a single day in 1969.
Anyway, Captain on the left. Many panels have one primary set of instruments, if you go back to older aircraft and GA aircraft the T Panel instruments are on that side only (although not always in the conventional T layout on some older aircraft where the designer planned the panel by puking on it and then cutting out holes where large clusters landed).