He's one of Wodehouse's lesser-known series heroes, without the fame of Jeeves & Wooster, the renown of the Empress of Blandings, or even the admiring cult of Psmith. By the time you discover Uncle Fred, you're hooked hard on Wodehouse, and casting about for everything by him you can find.
Uncle Dynamite is a fine Wodehouse novel, complete with an impostor at a country house, various young lovers with engagements that should be broken for the good of everyone, unpleasantly loud older men, and collections of strange-looking items. It all comes together very well, and Uncle Fred is quite quotable throughout.
If you've read a number of Wodehouse novels, nothing in this one will surprise you. But it will delight you, which is more to the point.