Was it true that in the UK and Australia, you'd have the switch toggle handle go down to turn the lights on?
Yes, and that's still the standard today, so the British rocker switch pictured above is in the "on" position.
I believe that at first it was the norm for switches to be up for on (perhaps influenced by early knife switches?), but somewhere in those early days of electric light the convention changed to down for on, and that's how it's been since at least the 1920s, if not before.
In fact more than once I've been asked by British tourists why American light switches are upside down!
If you look at the operating handles on main switchgear, as opposed to wall switches, it's been much more variable over the years.
The old pre-war metal-clad fuseboxes which had an operating handle on the side were always up for on (the handle generally having to be down in the off position to open the cover for access to the fuses). The post-war "consumer units" which had a main which more closely resembled a regular toggle were designed so that down was on.
In more recent years (say since the late 1980s/early 1990s) the main switches have reverted to up for on again. I've never seen any industry explanation as to why this is so, but I reckon it's because circuit-breakers have gradually become much more common than fuses in new installations since the 1980s, and since the breakers are always up for on, it makes sense to have the main operate the same way.
