The London Train Station is right next door to the Leaky Cauldron
The London Train Station is a vast building with many muggles in it, which is a point of great consternation to the wizards that must go through it to get their children to the Hogwart's express.
As you walk between platforms 9 and 10 you spot a portly woman with red hair, 5 children, and as many luggage carts heading trowards a pillar between the two platforms. You hear her grumbling about "bloody muggles" and follow her. She and her brood stop in front of third pillar of four between the platforms, they all look around with faces of concern and every now and then one kisses their mum and runs into the pillar. But for reasons physics definetly can't explain, they don't bounce off! Rather they go through. You run up to her and ask her how to get to platform 9 and 3/4, Lord knows all the conducters do is sneer at you and ask why you're wasting their time. She turns to you and smiles gently. She instructs you to run at the platform pillar and close your eyes. You do so. Boy, that Pillar must be getting close to you by now.