Job offers on London's public transport was definitely one of the incentives, but I've not heard of anything specifically related to Clapham Junction.
Here's an answer:
"The new arrivals were given temporary accommodation in the deep tube shelter on Clapham Common, which had previously been used as a bomb shelter and to house prisoners of war. Brixton was the nearest place for work and socialising, and the Mayor of Brixton extended a particularly warm welcome to the new arrivals."
It's from this explanation of the link between the Empire Windrush and Windrush Square: www.20thcenturylondon.org.uk/server.php?show=conInformationRecord.42
I think I probably got the bit of Clapham Junction misinformation from the notorious fantasist and self-appointed tour guide who runs the Juice Bar.


)
Whether that's totally down to not wanting to be around blacks I don't know....

Shame on you