Re: Another basic mistake.
Actually, there is an even more basic mistake than that. It wasn't the 'Spitfire' that saved the day during the Battle of Britain. It was the Hawker Hurricane that did the Lion's share of the fighting. But it wasn't as 'sexy' as the Spitfire --- so the propaganda arm of the government sidelined it in preference to the Spitfire. They wanted to show the British public that England could match any new technology that the Germans might possess. And even beat them - in terms of the most 'modern fighting equipment'.
That's how the Spitfire became everyone's 'Pin-up' Fighter. I don't doubt that would have been 'secret factories' building Hawker Hurricanes in those early days.
Finally, its worth mentioning the Miles M.20. Very few people know that there were plans to create this very cheap 'backyard' fighter. So once again the Myth of the Spitfire rules supreme.