What a history book would look like if Monty Python wrote it. However, the book is not a recent development, not even as recent a development as Monty Python. The listing in Amazon implies it was released in the 1990's--in fact, the first edition was in 1931, proving conclusively that the term "Good Thing" was not the invention of Martha Stewart.
It makes fun of English public school exams. It also makes fun of a host of other things, like the Celts, the Romans, Beowulf, Robin Hood, Americans, and just about any other group you care to mention. The kernel of its humour lies not only in references to the Pope's bosom, but in the fact that it is much more than "grossly inaccurate"--the authors intentionally distort, condense and confuse historical events in the stated goal of "consoling the reader. ...History is not what you thought. It is what you can remember." (Emphasis not mine).
A cartoon by John Reynolds labelled "Magna Garter", showing a king evincing delight at the sight of a stockinged foot, pretty much sets the tone. I recommend it highly. The book is a quick, easy read and is just as funny the 2nd, 3rd and nth time around. If you enjoyed the Black Adder series, this is compulsory reading.