Aren't we all being a bit too clever here in order to substantiate and event? Yes....by all means, links to websites, statistics, figures from the ONS, but why not take the bull by the horns.
You will know someone in their 60's or 70's who were in areas like Peterborough, Bradford, Leicester et Al and take them back to their birthplace, walk around the area and listen to what they say has changed.
In my opinion, that conversation will convince you, far more than statistics, of the clear and increasing Islamisation of England.