In case you're still not convinced to play The Getaway with the Eyewitness London book, here's an example of why it is better that way.
Without book: hey, what's that off to the right? It looks like a church or something. This game sure is detailed, too bad I don't know what I'm seeing.
With book: [Press pause, consult neighborhood street map and guide.] "All Hallows by the Tower. The first church on this site was Saxon. The arch in the southwest corner, which contains Roman tiles, dates from that period and so do some crosses now in the crypt. There is also a well-preserved Roman pavement in the crypt that at times is open to the public. Most of the interior has been altered by restoration, but a limewood font cover, carved by Grinling Gibbons in 1682, still survives. John Quincy Adams married in 1797 before he was US president. Samuel Pepys watched the Great Fire of 1666 from the church tower. Today there is a small museum, brass rubbing center, concerts and a book stall." -- p. 153.
They should really bundle this book with the game.