26,819. Yes, I cheated - I used tools. Except for the last place that I guessed. Had nothing to go on (no ability to scope out the area) except for a sunny 360-round panorama of a grassy clearing next to a lake with a single wind turbine in the background. I guessed somewhere in the US and whilst the country was correct, the accuracy was off. (Turned out it was somewhere in New Hampshire, I think).
All of mine, except for one, were in the United States.
Not cheating at all. There are no rules.
The BBC site appears to be using the old or retro version of Geoguessr. This has only the one choice of locations - all around the world, and the maximum points are a very strange number somewhere over 30,000.
I suggest trying the latest version at
www.geoguessr.com. Maximum points for each location are 5,000, so a total of 25,000 for the game. My record is somewhere over 24,900, with assistance from other tools. The new version also allows you to restrict locations. Options include the whole world (at least the parts covered by Streetview), selected countries and regions (including USA, Europe, Japan, United Kingdom), selected cities (including New York, San Francisco, London and Stockholm) or famous places around the world. I recommend trying it out, but be warned it is very addictive.
While it can be fun detective work to locate a place, the greatest buzz is when you instantly recognize a place and can locate it to within a few metres without any moving around, because you have stood in exactly the same place. Has happened to me twice, with a view of Hong Kong from next to Star Ferry at Kowloon, and Jackson Square in New Orleans.