where are the populated areas for Polish in London
Hammersmith has a large Polish community ..... just take a walk down King Street and you'll think you're in Poland !
There are a couple of Polish shops and there's POSK which I believe is the largest Polish Cultural Centre in UK - closest Underground station is Ravenscourt Pk
Nearby you have St Andrzej Bobola's catholic church which is in Shepherds Bush, and Ealing and Acton have a thriving Polish community also.