As British people, we shouldn’t be yapping about immigrants coming into your country and not assimilating. Simply due to the fact that the entirety of continental Europe knows that wherever we settle, odds are that, within a year, our knowledge of the language won’t be advanced enough to get us a pound of grapes at the local market (conversion of Ibs into kg aside). But rest assured! This says just as much about our hypocrisy as it does about humanity in general!
In fact, I would argue that wanting to stay with people who are culturally similar to you is inherent to human beings; as it is, in essence, wanting to remain within your comfort zone. However, it is important to concede that inherent does not imply irreproachable. So, if we want immigrants to step out of that comfort zone and participate in our British society, we should try to achieve that by setting the example abroad, and by being much, much more inclusive and welcoming at home.