I am the JRI-Poland Town Leader for Rawa Mazowiecka. My ancestors came from Rawa and Skierniewice too.
I don't know anything about the London Rawa association I'm afraid (I would be interested to know more), but I would hope to be able to help you with some Polish records. Please feel free to email me.
LEWKOWICZ, RYWAN, SZNIATOWSKI, BLANKIET, LASKY, BERGER, WRON, FAJBISIEWICZ (Rawa Mazowiecka, Aleksandrow Lodzki, Lodz)