Abu Baker and Umar were run-of-the-mill “false salafis”? 
England is a Christian nation because it calls itself that via its official church. If Muslims replace it with a mosque then it becomes a Muslim nation. Is this your goal? Replace the most successful laws in the world with medieval Arab shariah?
Show me that survey. Muslims are 3% of the UK population right now. Even* if *Muslims keep having 10 kids a piece they will not overtake the rest of society and reach a majority until the end of the century. This projection also assumes that “kafirs” in the UK continue to have low birth rates and that the UK continues to allow unfettered immigration for Muslims.
Face it: shariah will never reign in the land of the Union Jack. Immigrant birth rates decline when they move to advanced nations and the global trend of declining birth rates is hitting people from developing nations too now (i.e. Saudi Arabia down from 6.3 to 3.9 from 2000 to 2008, Pakistan down from 4.6 to 3.7) . In France Muslim women now have only as many kids as non-Muslim women. In Germany the gap is down to 0.5 more for Turkish women over German-born women (it was 2.0 in 1970 and 1.0 in 1996). And so on.
Besides, do you want to try to impose shariah in the UK? If Muslims pull that stunt anywhere in Europe there will be a swift reaction, perhaps even deportations. Listen to the BNP. Is this what you want? Do you think they are going to succumb to an Islamist takeover and throw away the laws and culture they developed over centuries for foreign, medieval Arab law? If you want shariah immigrate to one of the countries with shariah…