I'm not sure I can relate to your reading of the article. Your conclusion is: As far as I can see, this conclusion doesn't really differ from what is stated in the article. It says directly in the subheading that this trend was true for 'six months until September'. Then, in the body of the text it says: Essentially, it's saying the exactly the same as you: For a 6 month period solar beat coal, but coal will overtake it again as winter approaches and more electricity is required. Nowhere in the article is the claim made that the UK is no longer reliant on fossil fuels. Or that solar power has permanently overtaken them. I guess if someone read only the headline then they could be mislead into thinking what you fear they might. But to me, the article as whole seems pretty innocent and to the point.The article seems to be trying to paint a certain picture: solar is beating coal. That's true in the moment, false on an annual scale, and there's been no shift in reliance on fossil generation.
The trend is unlikely to continue. Because there is less sunlight and a rise in demand for heating and lighting during the winter months, coal will once again overtake solar.