How many nautical miles between London and Sydney?

Measuring the path using google Earth, by sea from London to Sydney using the Suez Canal was around 12,000 nautical miles. Using the Panama Canal was closer to 12,500 nautical miles using a similar method to draw the path on google Earth.This doesn't take into consideration the curvature of the Earth and both were as close as I could get to a direct sea route.

Using http://www.freemaptools.com/measure-distance.htm the direct or 'as the crow flies' route is a shade over 9,200 nautical miles.