What I'm gonna say is a cop-out, but anyways, here I go
Muggles don't see how these places really look to those in the wizarding world, due to enchantments and protections put on said places so that the Muggles will walk right by them, not notice anything special or interesting, and keep on going on their merry way. This way witches and wizards keep their world in secret. So, that could be a reasoning *cough*excuse*cough* to put whatever they want in the London front :shrug: