In the UK, people drive on the left side of the road and steering wheels are on the right side of the vehicle. However, in UFO's version of 1980s Britain, both of these have been reversed. The show's creators were simply going along with what was being predicted at the time, which was that the UK would switch its driving system sometime in the near future. That change never happened. Just as the U.S. was predicted to have switched to the metric system, which also didn't happen.
Gerry Anderson intended the second season of the series to focus on alien attempts to destroy the Moon. When "UFO" was cancelled, Anderson developed this idea into Space: 1999 (1975).
In reality the "Harlington-Straker Film Studio" is in fact BBC Elstree Neptune House, BBC Elstree Studios Eldon Avenue, Borehamwood. Better known these days as "Holby City Hospital "
How 'Skydiver''s fighter aircraft, 'Sky 1', re-docks with the submarine is a mystery since it is never shown.
When Gerry Anderson came up with the concept of alien invaders for his new show he was initially stuck on coming up with an original reason for them to invade earth in secret. It wasn't until he heard about the work of Dr. Christiaan Barnard and his pioneering first heart transplant operation that he thought that aliens coming to earth to steal human organs was a good plot for his series.