Not so
The big issue in UK following joining EEC was the vast number of Polish and East German immigrants that took over the construction jobs...plumbers...electricians...carpenters etc.
Meanwhile the islamics from Pookistan etc were "grooming" white teen girls for the slave trade.
The Poles migrated where there were jobs (Iceland was also a destination of Poles). I would argue over the East German thing...it’s very rare that some German (east or west type) does some job hunt deal in England. Present unemployment in Germany is the lowest of almost EU member.
Go look at the demographic layers for UK, Germany, Sweden, Netherlands Belgium and France. Almost every country has at least one-hundred ethnic groups existing. Go and ask locals where the migrants (not just Muslims) tend to locate...it’s all in highly urbanized areas. They follow the same trend that you’d see in Chicago or any US urban area. The middle-class and upper-class note the urban problem, and start to move outside of the metropolitan area (miles and miles away). So you end up with a decaying urban picture and cops looking over their shoulder.
In the UK case...competent Pole plumbers/electricians came in...offered dirt-rate pay-scale and Brit companies weren’t going to be competitive. You have the same issue in Germany where the Poles took over projects and did the work for less.