I feel like this would be a solid 4D Chess Strategy. White Nationalists pop-up in "solidarity" with the Muslims by also converting to Islam. Then, the new White Muslims start conversing with their non-White Muslim brothers about how best to make UK more of a Muslim country. Then convince the non-White Muslims to start promoting more traditional Islamic Values/Beliefs in the UK, while the newly converted White Nationalists merely show support for their Islamic brothers.
Could be entertaining.
I have no idea as I don't live there. I doubt there are any real numbers at this time. There most likely won't be until they really really take a hold in the country. I guess look at the countries they come from as they are mostly homogeneous in their flavor of faith.
Also, I do not want to "revert," not convert (that's the way Muslims see it,) to a faith of child rapists.
So I checked and it's not even close. Sunni Muslims are like 90% of the Muslims who've immigrated to the UK.