Children's fantasy story with dragons and St George

Question

I read this when I was in primary school, which means it was written before the very early 1980s. I suspect it was written by a Brit.

England is experiencing a long, hot, dry summer; it's hot enough that dragons start hatching out, and terrorizing the country.

A couple of kids decide to head off and figure out how to stop the plague of dragons - I can't remember if they intend to find him, but they ultimately find St George, and he checks his weather machine. There's a dial on the machine that's stuck, so England's been getting no rain, which means that the weather is dry enough that the dragons can hatch. They re-set this, and everything gets cleared up - I think the dragons all die off when it starts raining again.

There's one other scene that I can recall, that I'm not entirely sure is from the same book. Our questing children are up in the sky somehow, and stumble across the department that's responsible for making rainbows - there's a workcrew busy painting up rainbows to display in the sky the next time it's raining.

Answer 1

Is this Deliverers of Their Country (1985)...?

It was originally published as a short story in The Strand Magazine in May 1899. The author was Edith Nesbit, an English writer and poet.

From Goodreads:

When an unusual spell of warm weather hatches out several hundred thousand dormant dragons, Britain seems doomed to a fiery death. But young Harry and Effie do not give up, and eventually earn the gratitude of the entire nation.

From a blog:

When England is beset by a plague of dragons of all shapes and sizes, two heroic children first seek help from St. George, who is sleeping at St. George’s Church. (Nesbit lampshades how fortuitous it is that they go to the right church even though there are many churches with that name.) When he refuses to take on so many at once, they instead take his advice to find the Universal Tap Room, where bathroom taps are used to control the weather. They make England cold and rainy to drive off the dragons, which prefer sunny weather, hence explaining the climate of the country.