The article's basically a load of rubbish.
There's only a passing reference to the SBAs and even there they get it wrong.
They're obviously taking the theoretical maximum range of the S400 and extrapolating to its being able to shoot down aircraft at low level throughout.
They're doing what some do in here, regarding all aspects of the Russian military from a Marvel comics point of view. Missiles - any missiles - are still subject to the laws of physics. They have a destroy probability zone, an envelope. For any ground launched missile it has an increasing engagement height with distance parameter. Not to mention having to detect a target in the first place. Even if Turkey were to deploy the missiles to Cyprus (and why on earth would they do that??) they would still have to deal with the distance and terrain involved. From mainland Turkey they just couldn't do it.
What the article doesn't attempt to explain is why Turkey would want to shoot down British aircraft in Cyprus in the first place. As appealing an idea that might be to some.
Erdogan should aim his shiny new missiles at the Turkish economy. That's his biggest enemy.