England is quite multi racial and I would have thought that the Poles would fit in more than the Muslim communities
True, but there has never been a time when 200 000 Muslims came over every year for five years in a row, their number is higher but growth has been more gradual. And most were born here.
In fact, would an Englishman even recognize the Polish Language as being polish?
It's not just the language, it's the way they look/behave as well. And as the dominant "Eastern" European ethnic group in London, they aren't difficult to spot.
But let's face it, spoken Polish hardly sounds like French, Italian or Spanish. If I can tell the difference between someone speaking Urdu and another speaking Arabic, I'm sure an English person can tell the difference between Polish and French speakers.