Spitfires intercepting a formation of 20+ He 111s with a strong 40+ escort of Bf 109s including close escort and top cover during the height of the Battle of Britain in1940.

This is a heavily modded CFS3 install. Not all of the mods are publicly available. You can get the Spitfire here:
http://www.sim-outhouse.com/sohforums...

For the rest, I suggest Ankor's shaders available here:
http://www.sim-outhouse.com/sohforums...

An ocean color mod available here:
http://www.sim-outhouse.com/sohforums...

And the ETO Expansion available here:
http://www.sim-outhouse.com/sohforums...

These mods will get you close to what you see in the video, though not everything.